What request does the following SQL answer?
SELECT Instructor.Name, COUNT(*)FROM Instructor, TrainingEvent WHERE Instructor.Name = TrainingEvent.NameAND Email IS NOT NULLGROUP BY Instructor.Name;
a) It counts the number of instructors who have participated in training events and have an email address.
b) It lists the names of instructors and the number of training events they have attended.
c) It selects the names of instructors and counts the number of training events.
d) It displays the names of instructors who have participated in training events and have an email address.