To revise the sentence so that it uses the active voice, we need to make the subject of the sentence perform the action. In this case, the subject is "scientists." Here are the revised options:
1. Scientists reached a decision about when to begin the experiment.
- This revision changes the sentence to active voice by making "scientists" the subject performing the action of reaching a decision.
Out of the given options, this is the one that correctly changes the sentence to active voice by placing the subject "scientists" at the beginning of the sentence and showing them as the doer of the action "reached a decision." This makes the sentence clearer and more direct in conveying the message.
