Explanation
Correct answer: D.
Choice D is the best answer. The past tense of "suspended" matches the past tense of "applied," which has the same subject ("he") and takes place in the same context: "He applied…and [he] suspended."
Why the other choices are wrong
Choice A
Choice A is incorrect. The perfect infinitive "to have suspended" doesn’t match the past tense of "applied," and it can’t serve as a verb on its own. These are both verbs with the same subject and in the same context, so there’s no need to shift tenses.
Choice B
Choice B is incorrect. The present participle "suspending" doesn’t match the past tense of "applied," and it can’t serve as a verb on its own. These are both verbs with the same subject and in the same context, so there’s no need to shift tenses.
Choice C
Choice C is incorrect. The infinitive "to suspend" doesn’t match the past tense of "applied," and it can’t serve as a verb on its own. These are both verbs with the same subject and in the same context, so there’s no need to shift tenses.