When a new answer is approved on my site and a user is subscribed to the question category or the global categories, a notification email goes out with the subject "A question subscribed by you got an answer". This makes sense for a question that the user has subscribed to, but does not necessarily make sense for the category subscriptions.

On my site for category subscriptions, I would only like an email notification to go out upon a new question, not for new answers to questions. Is there a way I can disable the email above from being sent?