Why are mainframes considered more secure than LAN environments?

A.
They have fewer entry points.

B.
They have stronger authentication mechanisms.

C.
They have more auditing and encryption implemented.

D.
They are actually weaker than LANs.

Explanation:
This is a relative and general statement. Mainframes are more closed
systems and work in more closed environments when compared to the distributed
environments we work in today. Mainframes usually have a smaller number of entry
points, which are generally very controlled.