Question

And that decided it(voice change)

Answer 1

The above mentioned sentence is in active voice; therefore it is important to change the whole context into passive category.

One of the most important factors that have to be taken into account is subject.

Therefore the right answer is it was to be decided by that.

That comes right at the last of the sentence.

Answer 2

Hi,

here is your answer,

Question = And that decided it(voice change)

Answer = It was to be decided by that.

Hope it helps you !