母に七時に(a - 起きて・b - 起こして) 欲しいと頼んでおこう。

Question

母に七時に(a - 起きて・b - 起こして) 欲しいと頼んでおこう。

For the above statement I chose a - 起きて but it was wrong, why is b right and a wrong?

Answer 1

Grammatically, both a and b are possible. It is a matter of which situation is (by far) the commoner.

• 起きてほしい would mean ask mom to wake up;
• 起こしてほしい would mean ask mom to wake me up,

of which the latter is the likelier.