The correct answers are B) they were afraid they could not sail home against the winds and C) they had never sailed so long out of sight of land.
The two reasons why Columbus's crew threatened to mutiny were the following. They were afraid they could not sail home against the winds and they had never sailed so long out of sight of land.
Christopher Columbus and his crew had been navigated for weeks and there was no land in sight. The crew was getting desperate and started to feel fear. Provisions were scarce and they began to think the worst. Fortunately, on October 12, 1492, they saw an island on the horizon.