What is the man$-$in$-$the$-$middle threat for wireless LANs?

a$.$

The attacker impersonates an authorized user and gains certain unauthorized privileges to the wireless network.

b$.$

The attacker passively monitors wireless networks for data, including authentication credentials.

c$.$

The attacker steals or makes unauthorized use of a service.

d$.$

The attacker actively intercepts communications between wireless clients and access points to obtain authentication credentials and data.