To build upon puneetnanda's post, you should preference first-order effects over secondary effects.
Imagine if you had a question which asked you about the effects of a falling oil price on an energy-importing country, and two options included (A) lower inflation and (B) decreased income inequality. Now, whilst it is generally held by economists that (B) occurs as a result of (A), the correct answer is (A), because it is the most important effect, and is thus the most correct answer. (B) is something that occurs as a result of (A), and is something that you might select if you overthink the question.