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

<passage>:
The enemy was friendly enough. Trouble was—their friendship was as dangerous as their hate! melting, yes. Melting down at the bottom a little. Now it's falling over to one side and laying on the air tank. The air tank is getting red, too. I'm afraid ... it's weakening it.... Redder. Oh, oh." "What?" said Capt. Lawler. " Capt. Wilkins leaped from his position. He was still floating toward the ground when there was an incredibly lashed through the airlock and rolled across the lunar surface. The "There went the air," Capt. Lawler commented. "Boom! Boom!" said Major Winship in exasperation. "The one that doesn't speak English." "He's done it deliberately," said Capt. Wilkins, the eldest of the four Americans. "How are we going to know when it's over?" for several minutes. "Ah, it's all Russian. Jabbering away. I can't tell a thing that's going on." In the airless void of the moon, the blast itself would be silent. A Perspiration was trickling down his face. "Let's all go in," said the fourth American, Capt. Lawler. "It's probably over by now." Five minutes later, the perspiration was rivers across his face. "This is it," he said. "I'm going in." "Let's all—" "No. I've got to cool off." closing the door behind him. The darkness slowly filled with air, and the temperature inside the suit declined steadily. At the proper moment when the floor beneath him rose and fell gently, pitching him forward, off balance. He stumbled against the table and ended up seated beside "Charlie! Charlie!" There was a wait during which everyone seemed to be holding their breath. They began to get the static for the first time. It crackled and snapped in their speakers. They made sounds of disapproval at each He peeled back a marker and let it fall. Air currents whisked it away and plastered it against a riveted seam of the dome. It pulsed as though it were breathing and then it ruptured. Major Winship moved quickly to cut out the emergency air supply which "I don't think I've got enough pressure left to hold it, now. It's sprung a little, and I can't get it to conform over the rivet heads." There was a splatter of static. "Damn!" Major Winship said, "they should have made these things more flexible." to slide downward, then it fell away completely and lay limply on the floor. "Come on in," he said dryly. They huddled over the instruction sheet. "Let's see. Squeeze the tube until the diaphragm at the nozzle ruptures. Extrude paste into seam. Allow to harden one hour before service." Major Winship said dryly, "Never mind. I notice it hardens on contact It was an awkward operation that took several minutes. Capt. Wilkins cursed twice during the operation. "I'd hate to live in this thing for any period." sat with his back toward the transmitter. Capt. Wilkins slewed the They roused Earth. "This is Major Charles Winship, Commanding Officer, Freedom 19, the Leak? "... Freedom 19! Hello, Freedom 19! Come in!" Soviet Union fired an underground atomic device for the purpose of investigating the composition of the lunar mass by means of seismic analysis of the resultant shock waves. This was done in spite of American warnings that such a disturbance might release accumulated stresses in the long undisturbed satellite, and was done in the face of The turn was uncomfortably tight and complicated by the restraining cables. Capt. Wilkins began replacement of the air bottle. "Immediately following the detonation, Freedom 19 was called on to "However," he continued, "we did experience a minor leak in the dome, destroyed our organic air reconditioner. We have approximately three that, in the event we exhaust our air, we will be able to obtain the The wait of a little better than three seconds for the response gave the conversation a tone of deliberation. Methodically, Capt. Wilkins set about disconnecting the major from the transmitter. to get on the emergency channel to ask you to charge the air bottle. minute in my whole life. I didn't know how much emergency air was left, nickname being entered in my files: aka. The Airless Idiot. I tell you, III Capt. Lawler and Lt. Chandler returned with the calking compound. It The airlock to Freedom 19 was open. "What is "About this drum," Capt. Wilkins said. "Well, like I said, it's this way," Lt. Chandler resumed. "I told him we needed about a pint. Maybe a quart. But this stuff you have to mix up. He only had these drums. There's two parts to it, and you have to combine them in just the right proportion. He told me to take a little scale—" surprised look, like everybody, everywhere has dozens of little scales." "Well, anyway," Lt. Chandler continued, "he told us just to mix up the of calking compound. Those people are insane." "The question is," Capt. Lawler said, "'How are we going to mix it?' It's supposed to be mixed thoroughly." They thought over the problem for a while. we could...." It took the better part of an hour to rig up the electric mixer. Capt. Wilkins was profusely congratulated. the mixer out there." It took the four of them to roll the drum inside, rocking it back and forth through the airlock. At that time, it was apparent the table was interposing itself. Lt. Chandler tried to dismantle the table. "Damn these suits," he said. Eventually, they accomplished the moving. They wedged the drum between the main air-supply tank and the transmitter. They were all perspiring. "No!" Major Winship snapped. With the drum of calking compound inside, both Capt. Lawler and Lt. Chandler retreated to the bunks. Capt. Wilkins maneuvered the mixing attachment. "I feel crowded," he said. "Cozy's the word." "Watch it! Watch it! You almost hit me in the face plate with that!" "Sorry." At length the mixer was in operation in the drum. "Works perfectly," said Capt. Wilkins proudly. "Now what, Skip? The instructions aren't in English." "You're supposed to dump the bucket of stuff in. Then clean the area thoroughly around the leak." the drum. "We don't have any sandpaper." "It's been a long day," Capt. Wilkins said. "Mix it thoroughly," Lt. Chandler mused. "I guess that means let it mix for about ten minutes or so. Then you apply it. It sets for service in just a little bit, Finogenov said. An hour or so, maybe." "I hope this doesn't set on exposure to air." "No," Capt. Lawler said. "It sets by some kind of chemical action. General Finogenov wasn't sure of the English name for it. Some kind of plastic." "Larry," said Major Winship, "I wouldn't know a room-temperature-curing epoxy resin from—" "Hey!" exclaimed Capt. Wilkins. "The mixer's stopped." He bent forward and touched the drum. He jerked back. "Ye Gods! that's hot! And it's harder than a rock! It an epoxy! Let's get out of here." "Out! Out!" He and the Major reached the airlock at the same time and became necessity for speed, was doubly so. The other two crashed into them from behind, and they spewed forth from the dome in a tangle of arms and legs. The table remained untouched. When they halted, Capt. Wilkins said, "Get to one side, it may go off like shrapnel." They obeyed.

<question>:
What caused the explosion that resulted in the loss of air on Freedom 19?

<options>:
A The room became too hot from overcrowding
B The calking mixture leaked onto the air tank.
C The compound mixture became too hot because of the lack of the air reconditioner
D The compound mixture was mixed too quickly.

<answer>:

B