Correct Answer: The boys ate up all the biscuits.

Solution : The correct choice is the third option.

Explanation:
Active voice, or active form, refers to a sentence or clause where the subject performs the action expressed by the verb. In active voice, the subject is typically the doer of the action, and the sentence structure follows the pattern of subject-verb-object.

• Identify the subject: "The boys"
• Identify the verb: "were eaten up"
• Determine the object: "all the biscuits"

The structure of the active voice is as follows: Subject (The boys) + Verb (ate up) + Object (all the biscuits)

Therefore, the active form would be: The boys ate up all the biscuits.