Which Is the Best Counterexample to the Principle in the Following

Multiple Choice

Which is the best counterexample to the principle in the following Argument from Principle?
[Pay attention to the criteria for good counterexamples from Chapter 6 of Doing Practical Ethics.]
1) If lots of people do something, then it's not morally wrong to do it.
2) Lots of people drive a gas-guzzling car.
So, there's nothing morally wrong with driving a gas-guzzling car.

A) Not many people give lots of money to charity, but there's nothing wrong with doing that.
B) Lots of people held other people as slaves in the pre-Civil War American South, but that was clearly morally wrong.
C) Lots of people have abortions, but that's wrong.
D) If it's Hawaiian shirt day at your work, and lots of people are wearing Hawaiian shirts, then it's clearly not wrong for you to do so, too.