Translation:He is answering the question
Is present continuous implicit here? Answer and reply to are standard synonyms
No, present simple should also be accepted (and it was, just now).
"Answer" and "reply
to" are near synonyms but not quite a full match.
"answer" can be transitive (take a direct object - in this case "the question"). "reply" is intransitive ("reply to" + object, or just the verb alone: " 'Yes', she replied.")