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

<passage>:
never know. I never thought I'd mess around any of them, but things can sure happen. A man can get himself backed into a corner in this and talent likely to deprive the System of my activities—even experimenting with to rat on him before taking the job. Well, Casey Ritter may be a lot of things we won't mention, but he I didn't get it at first. I'd argued with 'em, but inside I'd been all set for the sentence, and even sort of reconciled to it. I could even hear the words in my mind. But they didn't match what the judge was I snorted. "Aw, hell, judge, that's just one of those screwy fairy tales! How could any—" "I assure you it is no fairy tale. We possess well-authenticated photographs of these inhabitants, and if you are prepared to visit them say, eminently suited to the task." He beamed at me. I looked around. They were all beaming. At me! Crude, but it was all I could squeeze out. I squeezed out more when I saw those pictures, though. Those inhabitants were charming, just charming if you like scorpions. Well, gangrene around the edges. The bleat of anguish that accompanied my first view of those beauties had taken my voice again. "How big?" I whispered. He shrugged, trying for nonchalance. "About the size of a man, I A crafty-eyed buzzard across the table leaned toward me. "So this is the great Casey Ritter, daredevil of the Solar System!" he sneered. "Never loses a bet, never turns down a dare!" They were really stumped. They hadn't expected me to take this attitude at all. No doubt they had it figured that I'd gratefully throw myself won't reach in and nip off an arm or leg while he's got his back turned. How stupid could they get? turned me into an honest trader. Me, Casey Ritter, slickest slicker in safe and secure in the grip of the good old Iron College, I relaxed. and after awhile I braced him. "Oh, a pretty good jolt if they can keep hold of me," he says. "I just He shrugged, but his little black-currant eyes began to sparkle with "I'd start more than that just to get me mitts on them stones again! Why, you ain't never seen jools till you've seen them! Big as hen's eggs, an even dozen of 'em and flawless, I'm a-shoutin', not a flaw!" His eyes watered at the memory, yearning like a hound-dog's over a fresh scent. of contemptuously but those Bleachies are a rough lot when they're nothing but a heap of cleaned bones by now. Either he was the world's champion liar or its bravest son, and either way I took my hat off to him. "How'd you make the getaway?" I asked, taking him at his word. somehow knew that he'd really lifted those emeralds. But how? It was with me. But he wouldn't tell me how he'd worked the steal. Instead, He looked at me as if I hadn't yet got out from under the rock where he was sure I'd been born. "Don't you know nothin', butterhead?" "Brains!" he snorted. "Have they got brains! Why, they're smarter than people! And not ferocious, neither, in spite of how they look, if you just leave 'em alone. That's all they want, just to be left alone. Peace an' quiet, and lots of methane and ammonia and arsenic, that's cheese trap, though, I figger she'll be all cooled off and ready fer nails, I bit myself. So I faced it. Casey Ritter lost his nerve, and along with it, the chance of a lifetime. A better man than me had that I could pry more information out of Pard Hoskins. while I sat around all hunched up, wondering feverishly if Pard would that was good training, so I sneered right back at him, explained the a-purpose to upset her." Then he winked at me. "But then I got off in a corner and cooked up some perfume that drives them nuts the other way put just a touch o' that there perfume on the outside of it. Akroida'll do anything fer you if she just gets a whiff. Just anything! But remember, don't use but a drop. It's real powerful." tiny bottle like that boy Aladdin clutching his little old lamp. slobbering. But the Big Sneer of the S.S.C., the fellow that had got me into this caper, was right there to take the joy out of it all and to remind me that this was public service, strictly. "These—" he had proclaimed with a disdainful flourish, like a placer miner pointing to a batch of fool's gold—"These jewels are as nothing, Ritter, compared with the value of the secret you are to buy with them. And be assured that if you're man enough to effect the trade—" He paused, his long nose twitching cynically—"IF you succeed, your That twitch of the nose riled me no little. "I ain't failed yet!" I was as nervous as a cat with new kittens. Feeling again for my little I eased along. though, I nearly lost my grip on the handle. In fact, I'd have fainted lived. If that little shrimp could do it, I could, too. intimate—or rather, the taps were. There was even a rather warm expression discernible in the thing's eyes, so I took heart and decided to ignore the ferocious features surrounding those eyes. After all, the poor sinner's map was made of shell, and he wasn't responsible for its expression. I tapped back very politely that he must be mistaking me for someone else. "I've never been here before, and so I've never met the charming be interested." He reared back at that, and reaching up, plucked his right eye out of out thoughtfully, just like an ordinary business man, and I managed to A shudder of ecstasy stiffened him. His head and eyes rolled with it, Taking advantage of his condition, I boldly tapped out, "How's about I tried to back off from him a bit, but the ship stopped me. "I'm Casey I breathed again. How simple could I get? He'd already mistaken me for Pard, hadn't he? Then I remembered something else. "How come you aren't mad at him? Don't you hate yellow, too?" He hung his silly head. "I fear I am colorblind," he confessed sadly. Right there I forgave him for pulling that eye on me. He was the guide I needed, the one who had got Pard out alive. I almost hugged him. alive but loved and cherished, thanks to Pard's inventiveness and to mandibles and other embellishments calculated to interest my hosts. Whether it interested them or not, it was plenty uncomfortable for me. and peaceable manner that almost made me forget that I was scared to death of them, and they stared at my boat with only a mild interest that would have taught manners to most of my fellow citizens of Earth. Pard was right again. These critters had brains. And my S.S.C. persecutor was right, too. That anti-grav secret was worth more than what about Casey Ritter, who hadn't cultivated even a feather? here and there as though she was just itching to take a hunk out of somebody, and the way the servants were edging away out around her, I could see they didn't want to get in range. I didn't blame them a bit. could hear her question reverberate away over where I was. That conversation was telegraphed to me blow by blow by the actions of direction. "Casey Ritter? Never heard of him. Where's he from?" ducked his head and fearfully waited.

<question>:
What did Casey probably learn from this experience?

<options>:
A Never give up on your friends
B Never trust a crook
C Always listen carefully to instructions
D Don't judge others by how they look

<answer>:

B