【单选题】An employee cannot access the company database. You check the connection variables: What is a valid explanation for why one of the users is unable to connect to the database?()
A.
Bob has max_user_connections set to zero, which blocks all his connections
B.
Joe has exceeded the max_user_connections global limit
C.
All users are blocked because max_user_connections is accumulated over the host account information
D.
Kay is already connected elsewhere and attempting to log in again
E.
Connect_timeout is too small to allow a connection to occur