The IEEE 802.11 pairwise transient key (PTK) is derived from what cryptographic element?

A.
Phase shift key (PSK)

B.
Group master key (GMK)

C.
Peerkey (PK)

D.
Group temporal key (GTK)

E.
Pairwise master key (PMK)

Explanation:
http://www.scribd.com/doc/33436351/43/IEEE-802-11i-and-WPA2 The pairwise master key (PMK) is used to create the pairwise transient key (PTK)