At what MAC layer transmission rate does an HR-DSSS access point send Probe Response frames?

A.
Always at 1 Mbps.

B.
At the highest rate supported by both the access point and client station.

C.
At the highest basic rate configured on the access point.

D.
At the lowest basic rate configured on the access point.

E.
At any rate supported by both the client station and the access point.