He knew that
P : and then to save himself
Q : was to save all the lives
R : entrusted to his care
S : the duty of a captain

The Proper sequence should be:

A. PQRS

B. SQRP

C. SPRQ

D. QSRP

Answer: Option B

Solution(By Examveda Team)

He knew that the duty of a captain was to save all the lives entrusted to his care and then to save himself.