B. Trivial vs crucial decisions.
The story mentions family and he did command a ship but a theme is a general, underlying thing that shapes the story itself. The navy guy wouldn't be feeling any of this if he hadn't seen suffering and violence and stress during his time at war. So it influences his behaviour with his family/friends at home. Therefore, the theme of the story is about the importance of life decisions. He no longer views these minute things (like vacation spots and home decor) as important.
Can you be more specific on the question please
"To try to write certain sentences is difficult"
The correct statements are 1, 2 and 3.
1) The sentence is correctly written. The pattern "to try to do something" is correct and can be used.
2) The sentence contains more than one infinitive. It contains two infinitive verbs. TO TRY and TO WRITE.
3) One infinitive is inside another infinitive phrase. "To try to write certain sentences" is an infinitive phrase, it functions as a noun because it is the subject of the sentences. So, the second TO INFINITIVE is inside the main infinitive phrase. (That is the reason why number 4 is not correct)
The answer is c) Knight and the Prioress