A sentence has been given with a blank to be filled with an appropriate option. Choose the correct alternative.

I ____ the cake before my mother arrived.

had baked 

The correct option to fill in the blank is Option 1: had baked

The use of “before my mother arrived” shows that one action happened earlier than another action in the past. To express an earlier past action, we use the past perfect tense (“had + past participle”). Here, “had baked” correctly indicates that the cake was baked before the mother arrived.