Explanation:

- The passage discusses making personal choices, especially regarding one's subject of study.

- Blank (1) calls for a word expressing reliance on one's own decision-making, likely "judgment" or "instinct".

- The second blank, "regarding" or "of," introduces a topic related to the choice.

- The phrase "(3) _________ one is genuinely interested in a subject" implies that a condition should be met.

- Blank (4) requires a verb indicating preference or necessity when interest is absent.

- "Ought" implies a strong suggestion or moral obligation but is less direct.

- "Would" is a future conditional and doesn't fit the context.

- "Could" indicates possibility, not necessity.

- "Should" expresses advisability and aligns with the context that without genuine interest, opting for a subject is inadvisable.

- The phrase "unfit for their roles" highlights the consequences of ignoring one's genuine interests.

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