(A) claims the physician assumes hormones are the primary factors accounting for the difference. The physician does assume hormones play a causal role, but he doesn't need to assume they're the most important factor. His conclusion is just that testosterone "tends to promote" and estrogen "tends to inhibit" heart disease. That's a claim that these hormones have some causal influence, not that they're the main driver. You can believe a factor contributes to something without believing it's the primary contributor.

Like (A), this answer goes further than what the physician assumes. The physician concludes that testosterone promotes and estrogen inhibits heart disease. But he never claims these are the only hormones that matter. There could be dozens of other hormones that also affect heart disease risk, and that wouldn't undermine his conclusion. His argument would still work as long as testosterone and estrogen each have the effects he attributes to them, regardless of whether other hormones also play a role.

The physician never makes this comparison. His argument is structured around two separate observations: men get heart disease earlier (correlated with high testosterone), and women get heart disease after menopause (correlated with losing estrogen). He doesn't need to compare the risk levels of high-testosterone men against postmenopausal women to reach his conclusion. These are two independent pieces of his reasoning, not a single comparison between those two groups.

This captures the flaw. The physician's entire argument rests on observed correlations: testosterone levels are higher in the group that gets heart disease earlier, and estrogen drops right before women start getting heart disease. From these correlations, he concludes that the hormones themselves influence heart disease. But he provides no evidence that the hormones are actually doing the causing. Maybe men get heart disease earlier because of some other biological difference between men and women that has nothing to do with testosterone. Maybe women get heart disease after menopause because of some other change that happens during menopause besides losing estrogen. Without ruling out these possibilities, the physician is assuming that because the hormone levels track with heart disease patterns, the hormones must be part of what's driving those patterns.

The physician's argument is based on general trends ("generally affects men at an earlier age," "tend to experience"). He's not assuming that every person of the same age and gender has identical hormone levels. Even if hormone levels vary from person to person, the general correlations he cites could still hold. Individual variation doesn't undermine an argument built on broad patterns.