While on the lifeboat, why does pi throw himself at the hyena?

a) he no longer cared about the zebra
b) he was hopeless and angry after the zebra's death
c) he was attempting to secure a food source
d) he wanted to see if he was stronger than the hyena

the author regularly mentions the story of pi will have a happy ending. why?

a) he doesn't want to become depressed.
b) he wants readers to finish the story.
c) it's a lie. there is no happy ending.
d) he likes to increase plot suspense.