The correct answer is A. PQRS.
The sentence is about the duty of a captain. The captain’s duty is to save all the lives entrusted to his care, and then to save himself. So the correct sequence is P-Q-R-S.
Option B, SQRP, is incorrect because it puts the second part of the sentence, “and then to save himself,” before the first part, “was to save all the lives entrusted to his care.” This makes the sentence illogical.
Option C, SPRQ, is incorrect because it puts the second part of the sentence, “and then to save himself,” in the middle of the first part, “was to save all the lives entrusted to his care.” This makes the sentence difficult to read and understand.
Option D, QSRP, is incorrect because it puts the second part of the sentence, “and then to save himself,” at the end of the sentence. This makes the sentence seem like the captain’s duty is to save himself, and then to save all the lives entrusted to his care. This is not the correct order of priorities.