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

<passage>:
Don't get me wrong. Kids are great. I have some, and I adore them. Every Christmas I become a slave to my camcorder. Tiny tots with their eyes all aglow, and so on. But now that the radiance of the yuletide season is fading, it's time to confront a sobering scientific truth: The more you think about the biology of parental love, the more absurd it seems. The same goes for love of kin generally--brothers, sisters, nephews, etc. Thanks to the biologist William Hamilton, it is now clear why people feel brotherly love in the literal sense--and sisterly love, maternal love, and paternal love. It's all due to the operation of "kin selection" during evolution. A greatly oversimplified textbook example: Two million years ago, two hominids, Loveless Bob and Loving Bob, stand on two different riverbanks, in identical situations. Each is watching his full sibling Bill drown. Loving Bob has a gene inclining him to love his brother and thus jump in the raging river, even though his risk of dying is 10 percent. Loveless Bob has no such gene, and thus stands on the bank wondering whether his brother's corpse will attract any large, edible fish. Which Bob's genes will survive the Darwinian reaper--genes for love or for cold indifference? Love triumphs. True, there's a one-in-10 chance that the love gene will sink along with Loving Bob. But consider the upside. There's a one-in-two chance that Bob's full sibling Bill has the same gene and, thus, that a successful rescue mission will pluck an otherwise doomed copy of the gene from the dustbin of history. Do the math, and you'll see that, over time, Loving Bobs send more genes to posterity than Loveless Bobs. As love genes spread at the expense of indifference genes, Loveless Bobs slowly become extinct. Die, selfish scum! Genes for sibling love come to permeate our species--as, in fact, they now do. So do genes for maternal love and paternal love. All brought to you by kin selection. As modern Darwinism gets popularized, the basic idea of kin selection is approaching the status of conventional wisdom. So are some attendant misconceptions. Misconception No. 1: Genes are smart . People often assume that kin-selected altruism is foolproof For example: Back when Loving Bob was 6 years old, if his mother was nursing some infant named Bill and sleeping by its side every night, there's a very good chance that Bill was Bob's sibling. So a gene disposing Bob to love children whom he sees his mother nurturing could spread through the population until everyone obeys the same rule. But this rule would misfire now and then, when a mother is for some reason nurturing a non-offspring. It's just that the misfiring wouldn't happen often enough to greatly dilute the genetic math favoring the gene's proliferation. Anyway, the main point is that when genetic parents give up a child for adoption and have second thoughts weeks, months, or even years later, their appeals to blood ties should count for zilch. Their love of their child, and their child's love of them, depends not on genetic math but on a long and complex chain of bonding, much of which they have already voluntarily missed out on. Similarly, the idea that Native American babies, or black babies, or whatever, have some mystical genetic affinity with their "own" kind is silly. Obviously, cross-ethnic adoption is dicey. It draws sidelong glances and playground taunts, and it may give the adopted child an identity crisis. But it won't do this because of some ancestral memory in the genes. As attitudes change, cross-ethnic adoption will get easier and as cross-ethnic adoption gets more common, attitudes will change. (There are other pop-genetics arguments against cross-ethnic adoption, and against adoption in general. One is that genes influence personality so powerfully that mixing unrelated siblings is like mixing oil and water. This idea is .) Misconception No. 3: Our genes, though perhaps not real smart, aren't downright stupid . Here we come, at last, to the true absurdity of familial love. As we've seen, the genes that sponsor it flourished by encouraging an "altruism" that was, in fact, self-serving at the genetic level (the inexorable triumph of Loving Bob's genes). As we've also seen, these genes can be "fooled" into encouraging altruism toward non-kin, altruism that presumably is not self-serving at the genetic level. Still, you might argue, in defense of your genes, they usually direct familial love toward genuine kin, and thus usually succeed in being efficiently selfish. Wrong! When genes confine altruism to kin, and deny it to needy non-kin, they are in fact failing spectacularly to be efficiently selfish. Because nowadays, copies of these genes do reside in non-kin--in your next-door neighbor and, for that matter, your worst enemy. After all, the Darwinian logic behind love of kin was so relentless that these genes permeated our entire species! Loveless Bob is extinct, remember? You can be forgiven for doubting my logic. People like me, in writing about kin selection, often talk about full siblings sharing "half their genes," implying that nonrelatives share none. But in truth, you share virtually all your genes with any randomly selected homo sapien on any continent. What people like me really mean is that full siblings share half of any genes that are newly minted--genes that have recently arisen and on which natural selection is just starting to pass judgment. Genes that natural selection fully endorsed long ago--the basic genes for hunger, for lust, for familial love--are in everyone. So genes that originally flourished by bestowing love with discerning selfishness--by discriminating against people not containing copies of themselves--now, having spread through the species, discriminate against people who do contain copies! You may doubt that natural selection, a process that supposedly maximizes genetic selfishness, could fail so abjectly to do so. But it's true. . So this past holiday season, as you rushed to buy presents for your kids or your siblings or your nieces or nephews, impelled by "selfishly" altruistic genes, you were operating under flawed Darwinian logic. These "selfish" genes could do just as much for themselves by encouraging you to instead spend your money on the beggar outside the department store. In fact, they could do more, since the beggar is closer to perishing than your relatives are. (Also, the beggar might buy something useful such as food, as opposed to a hair-eating Cabbage Patch doll.) But our genes are too stupid to so deftly serve their own welfare. Not that I attach much weight to what is and isn't "good" from the standpoint of genetic self-interest. As virtually all ethical philosophers who have pondered the matter agree, it doesn't make sense to model our moral values on the logic of nature anyway

<question>:
Why is it that loving family members like siblings can lead to individual biological success?

<options>:
A We want to see them succeed, so we experience chemical shifts when we see that they're happy.
B If we help them survive tough experiences, we'll learn to not make those mistakes (increasing our biological odds of procreating and being evolutionarily successful).
C If we help them succeed biologically, when they have kids they pass on DNA that matches some of our own.
D Biologically speaking, we share in the successes the exact same way that our siblings do because of genetic similarity.

<answer>:

C