Passive voice is a grammatical structure in which the subject of the sentence is acted upon by the verb, rather than performing the action. In passive voice constructions, the focus is often on the action itself or the recipient of the action, rather than on who or what is doing the action.
For example, in the active voice, you might say, "The chef cooked the meal." In passive voice, this becomes, "The meal was cooked by the chef."
Based on the options you provided, the best response to describe passive voice would be that it is a grammatical structure used to describe events that have already taken place, but it doesn't fully capture the essence of what passive voice is.