Question

A decision was reached by scientists about when the experiment would begin.

Which revision changes the sentence so that it uses the active voice?

Before the experiment by scientists, a decision was reached.
Scientists reached a decision about when to begin the experiment.
A decision was reached with scientists about beginning the experiment.
The beginning of the experiment is a decision that was reached by scientists.

Answer 1

Scientists reached a decision about when to begin the experiment.

This is active voice because "Scientists" (the subject) performs the action "reached."