No flaw. The sufficient conditions in (A) do connect to one another. Studying ancient art leads to appreciation of a certain aspect of ancient art, and that appreciation leads to a deeper understanding of modern art. It therefore follows that studying ancient art can potentially create new appreciation for modern art.

This provides two distinct sufficient conditions and assumes that they’re connected. Both learning Latin and studying literature can improve one’s vocabulary, but there’s no reason to believe that learning Latin always leads one to study literature.

Wrong flaw. This gets the conditional relationship backwards. From (C), we can infer that traveling to other countries can encourage one to study history, not the other way around. The stimulus doesn’t get a conditional chain backwards; it mistakenly assumes that two independent conditions are linked.

Not a flaw. This establishes that two practices related to study can help one develop and retain habits that will help one professionally. It’s therefore reasonable to conclude that diligent study can improve one’s chance of professional success.

Not a flaw. This establishes a conditional chain. If one reads the newspaper daily, then one can become informed about the world. If one is informed about the world, then one has appreciation of other cultures. It therefore follows that one can come to appreciate other cultures by reading the newspaper daily.