A. The mother called her son for lunch.
The verb in the sentence uses active voice because the subject of the sentence is the one doing the action stated by the verb.
The mother is the subject of the sentence. She is the one doing the verb "called". Therefore, the verb is using the active voice.
The other choices are using passive voice because the subjects are not the ones doing the action. Instead, the subjects are the recipient of the action or verb.
