Which is the active voice of: “The house had been broken into by someone”?

MCQ Quiz

1. Which is the active voice of: “The house had been broken into by someone”?

a
Someone had broken into the house while the owners were on vacation.
b
Someone had broken the house while the owners were on vacation.
c
The house had broken by someone while the owners were on vacation.
d
The owners had been broken into by someone while on vacation.