(Criteria after aggregation) Based on the conference database on the website, write SQL queries to for the following tasks: A Show the first and last name of all speakers who are appearing in least three sessions. Also show the number of sessions each such speaker is appearing in, labeled NumSessions. B Show the first and last name of all speakers who are appearing at least two sessions being held in rooms with a large screen. Also show the number of such sessions, labeled NumLargeScreen. C Show the ID and capacity for each room in which at least three sessions are being held. Also show the number of sessions being held in each of these rooms, labeled NumSessions.