Understanding the argument -
Ideally, scientific laws should display the virtues of precision and generality, as do the laws of physics. - Examples the Newton's laws. They are precise and, at the same time, general. You can apply the law in the US, India, Europe, or anywhere; it works. It'll give a precise value and be general enough that it works everywhere.
However, because of the nature of their subject matter, laws of social science often have to use terms that are imprecise; for example, one knows only vaguely what is meant by "republicanism" or "class." - However, it introduces a contrast. This means the laws of social science use imprecise terms.
As for generality, laws that apply only in certain social systems are typically the only ones possible for the social sciences. - Means the possible laws in social sciences are the ones that apply in certain social systems - they are not general.
Which one of the following statements is most strongly supported by the information above?
(A) All else being equal, a precise, general scientific law is to be preferred over one that is not general. - because that's the table stake in Scientific law. It has to be precise and general. ok.
(B) The social sciences would benefit if they redirected their focus to the subject matter of the physical sciences. - No mention of recommendation for social scientists to now start their focus on physics or scientific laws. Wrong.
(C) Terms such as "class" should be more precisely formulated by social scientists. - No mention of focusing on this.
(D) Social scientists should make an effort to construct more laws that apply to all societies. - The argument mentions that they use uncertain terms and are limited. It doesn't mention what to do. This is out of scope.
(E) The laws of social science are invariably not truly scientific. - The argument shares that they use imprecise terms and are not general. But saying that they are not truly scientific is beyond the scope of the argument. Broadly speaking, it is possible that a narrow social law is very scientific.