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 Absurdity of Family Love 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. Readers familiar with my obsessions may fear that this column is just another attempt to spoil everyone's fun, to replace the beautiful mystery of life with ugly Darwinian clarity. Actually, what I hope to dispel isn't pre-Darwinian mystery, but a kind of post-Darwinian mysticism, a confused exaltation of genetic affinity. You see the confusion when biological parents invoke "blood ties" to reclaim a child from adoptive parents. You see it when opponents of cross-ethnic adoption argue--as in a New York Times op-ed piece a few months ago--that we must respect "the strength of the biological and cultural ties that Indian tribes can offer their own children." In a sense, you see it every year around Christmas, when people pay lip service to the idea of universal brotherhood but believe in their hearts that it's ridiculous, that truly loving people to whom you aren't related violates some law of nature. 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 This irrelevance of genes is why surrogate motherhood is so messy. Even when, thanks to in vitro fertilization, the birth mother is unrelated to the fetus she carries, she will, upon giving birth, fall in love with the child. During evolution, after all, having a baby come out of your womb was reasonably strong evidence of kinship. The power of the hormones that govern this bonding is familiar to anyone who has watched a woman clutch her just-born child and turn into a love-drunk cuddle-bunny. (When my wife went through this magic moment, I briefly considered snatching the baby and replacing it with an 8-by-10 glossy of myself.) This hormonal power was also observed by researchers studying oxytocin, a hormone that's present in human and other mammalian mothers at birth. The researchers put it in a syringe and used it to shatter all previous records for cuddling among laboratory rats. By the way, the synthetic version of oxytocin, Pitocin, is what doctors use to induce labor. Misconception No. 2: People are smart--or, at least, they are smart Darwinian robots . Darwinian theory does posit that homo sapiens were "designed" to get their genes into the next generation, but not that they were designed to do so consciously and rationally. As surrogate mothers have proved, knowing that you've given no genes to an infant needn't stop the bonding process. Thus, "kin- recognition mechanism" is a doubly misleading term--first because, as we've seen, the mechanism doesn't positively identify kin, but just identifies factors correlated with kinship and second because people aren't really aware of doing the identifying. We don't think, "There's strong evidence that she's my daughter, so I adore her." More like, "God but my daughter's adorable." 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 .) 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 to infer ought from is --to commit the "naturalistic fallacy"--only leads to moral confusion. For example, you might, after observing the natural behavior of praying mantises, be tempted to conclude that it is morally good for females to eat males after sex--and this, I submit, would be a repugnant and wrongheaded doctrine! (Though slightly less repugnant than the idea of eating males before the sex.) Most people implicitly recognize the naturalistic fallacy in some contexts. They sense that there's something visceral about, say, malice yet they'll tell you (when not in its thrall) that they disapprove of it. It's obvious, they believe, that the natural strength of hatred is not a good thing. They're right. What is equally right, but a bit less obvious, is that the "natural" limits of love aren't necessarily good either. And, on close inspection, these limits turn out not to be all that rigorously "natural" anyway.

<question>:
What is the overall tone of this article? Are there any changes in tone over the course of the article?

<options>:
A The overall tone is conversational, with the occasional funny moment or comedic example.
B The overall tone is academic, with very few tonal changes (if any).
C The overall tone is academic, with a few emotional sections to evoke pathos.
D The overall tone is calm, with only a few tonal changes when the author tries to drive home a point.

<answer>:

A