Explaining an action with an unknown subject is
A: passive voice
B: active voice
A: passive voice
A: passive voice
The correct answer is A: passive voice.
When explaining an action with an unknown subject, we often use the passive voice. In the passive voice, the subject of the sentence receives the action, instead of performing it. This allows us to focus on the action itself without specifying who is responsible for it.
For example, if we say "The car was stolen," we are using the passive voice. We know that the action (stealing) happened to the car, but we do not specify who performed the action.