Change the following sentence into active voice by choosing the correct option.

All his calculations have been proved wrong.

They have proved all his calculations wrong.

The correct answer is Option (2) - They have proved all his calculations wrong.

In the active voice, the subject performing the action is explicitly stated. In this case:

• The passive sentence "All his calculations have been proved wrong" is transformed into active voice by introducing the doer of the action (e.g., "they").
• "They" is a common generic subject in such sentences when the actual doer is not specified.
• "It has proved all his calculations wrong" - This assumes "it" as the doer, which is incorrect in the context.
• "We have proved all his calculations wrong" - This is active voice but alters the meaning by introducing "we" as the subject.
• "All his calculations were proved wrong" - This is still in passive voice.