In which of the following plots would the setting contribute the most to the conflict?
a. a story about two people arguing over money
b. a story about a woman training a dog
c. a story about two campers trying to survive in a blizzard
d. a story about two brothers fighting for the same position on a team

Betray, destroy, and obey do not need to be changed to add the suffix -ed, because the "y" at the end of each word is preceded by a vowel  (so  they would be spelled  "betrayed," "destroyed," and "obeyed").

but hurry is different; it has to  be spelled "hurried" because the "y" at the end of "hurry" is preceded by a consonant.