Read the following passage and questions, then choose the right answer from options, the answer should be one of A, B, C, D.

<passage>:
or initiated entirely on the Sun, a miserable about it. If only we can He went from green to Puffyloaf white and blurted: "All right, I did it, but it was the only way out! Yesterday morning, due to the Ukrainian crisis, the government stopped sales and deliveries of all strategic stockpiled materials, including helium gas. Puffy's new program of advertising and promotion, based on the lighter loaf, was already rolling. There was only one thing to do, there being only one other gas comparable in lightness to helium. I diverted the necessary quantity of hydrogen gas from the Hydrogenated Oils Section of our Magna-Margarine Division and substituted it for the helium." "You substituted ... hydrogen ... for the ... helium?" Phineas T. Gryce faltered in low mechanical tones, taking four steps backward. "Hydrogen is twice as light as helium," Tin Philosopher remarked judiciously. "And many times cheaper—did burped aside for pickup by the feebly. "Yes, I substituted hydrogen. crawl trucks of a chemical corporation, the kernels quick-dried The metal-foil wrapping would the hydrogen loaf. But—" you know that?" Roger countered have added just enough weight to counteract the greater buoyancy of time infused with gas from a tank conspicuously labeled "Carbon Dioxide" ("No Yeast Creatures metabolism whether fast or slow, off for the day's consumption, the majority stored for winter in brightened. "Oh, boy—hydrogen! technique, which we've been saving not noticing the difference, proceeded of the hydrogen loaf carries then suddenly scattered, screeching in panic. are at this moment cruising eastward over Middle America. Remember that a six-month supply for deep-freeze is involved and that eight and one-half loaves per person per day." Phineas T. Gryce carefully inserted Christian prayers, had just reached the petition for daily sustenance, when a sub-flight of the loaves, either forced down by a vagrant wind or lacking the natural buoyancy why cried with a hysteria that would have dumfounded her underlings, shut the airlock after you?" the Golden Glacier said in tones not unkind. "When are your high-strung, judiciously. "The way sales have been plummeting, it won't be long before the Government deeds our desks to the managers of Fairy quick thinking come into this, Mr. Snedden? You can't be referring to the helium—that was Rose Thinker's brainwave." She studied him suspiciously. most of the sealed plastic wrappers into little balloons, which ruptured, when pierced, with disconcerting pops through the crusts had now distended while local and national governments raged indiscriminately at Puffyloaf and at each other. Rumors that a fusion weapon the flying bread drew angry protests from conservationists and a flood Thinker, whose bright relays genius-sparked of until that moment and reaffirmed India's ability to feed her population with no outside help except the usual. to taking up permanent aerial residence "such as we have always Phineas T. Gryce, escaping from his own managerial suite, raged about the city, demanding general appeared and before they involved captured by Tin Philosopher, escaped again, and was found posted gentlemen. This is a historic occasion in Old Puffy's long history, the inauguration of the helium-filled loaf ('So Light It Almost Floats Away!') in which that inert and with oxygen mask and submachine gun Customs and the State Department. Recaptured by Tin Philosopher, carbon dioxide. Later, his company in more trouble with who suffered only minor bullet heaven-aspiring gas replaces old-fashioned "By the by, Racehorse, that was a brilliant piece of work getting the helium out of the government—they've been pretty stuffy lately about their monopoly. But first I disappeared into a high Atlantic overcast, also thereby evading a local storm generated by the Weather Department in a last-minute holes, he was given a series of mild wide. Tin Philosopher coughed to limber up the diaphragm of his by Communist and Capitalist governments seriously interfered with military trailing of the flight during effort to bring down or at least disperse the H-loaves. speaker and continued: interpreting it as a call to charity, their hair-splitting insistence on the colorless substitutes were last reached their maximum altitude. The Sun's rays beat through the rarified air on the distended plastic wrappers, increasing still further the pressure of the confined hydrogen. They burst by the millions and tens of millions. A high-flying down into the starving Ukraine. Shaken by a week of humor that besides forming the backbone of bread, was quietly destroyed. Congratulatory notes were exchanged by various national governments bread flight was over, though for several weeks afterward scattered falls of loaves occurred, giving rise Back in NewNew York, the managerial board of Puffy Products slumped in utter collapse around the conference table, the long crisis session at last ended. Empty coffee cartons were scattered the baking art was the substitution of purified carbon dioxide, recovered from coal smoke, for the gas . But even purified carbon dioxide is itself a rather repugnant gas, a product of old carbon-dioxide stock from our freezers! It's almost exhausted, but the government, now that the Ukrainian crisis is over, has taken the ban off helium and will also sell us stockpiled wheat if we need it. We can have our walking mills what may be the ultimate step toward purity: we are aerating our loaves with the noble gas helium, an element which remains virginal in the face of all chemical temptations helium, which, if it be a kind of ash, is yet the ash only of hydrogen non-explosive or the helium loaf float just a little—" "I'm sure we can take care of that quite handily," Tin Philosopher helium loaf!" WITHOUT changing expression, radioactive burning, accomplished Phineas T. Gryce rapped figure out some way to make interrupted briskly. "Puffyloaf has kept it a corporation secret—even you've never been told helium loaf selling?" The business girl clapped on a pair of earphones and whispered for just such an emergency, it will hydrogen loaf." "Good!" Roger cried. "We'll tether 'em on strings and sell 'em like balloons. No mother-child shopping team will leave the store be possible to bake a helium loaf as buoyant in every respect as the balloons will be the big event of the day for kiddies. It'll make the carry-home shopping load lighter there has not been one single delivery of three to one—and that's just the So far this morning, sessile shops." "Mr. Snedden!" Gryce barked. "What bug in the new helium process might account for this delay?" unless—just possibly—there's order for metal-foil wrappers, assumed it was some sub-secretary's mistake, and canceled it last night!" Roger Snedden turned pale. "You canceled it?" he quavered. "And told them to go back to the lighter plastic wrappers?" "Of course! Just what is behind were you trusting, when our physicists had demonstrated months ago that the helium loaf was safely stackable in light airs and gentle breezes—winds up to Why February 1958. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed. Minor spelling and typographical errors see, the fact is that I...." "Hold it," Meg interrupted crisply. "Triple-urgent from Public Relations, Safety Division. Tulsa-Topeka fences. After grounding safely near Emporia—no fatalities—pilot's windshield found thinly plastered

<question>:
What was the main reason for hydrogen being substituted for helium?

<options>:
A It was much cheaper
B The helium made the loaves taste bad
C Helium would make the loaves too light
D The government halted supply of helium

<answer>:

D