which two methods are most commonly deployed?

In PPPoA architecture, which two methods are most commonly deployed? (Choose two)

A.
Terminating PPP sessions at the service provider

B.
PPP framing

C.
PPP multiplexing

D.
GRE tunneling

E.
L2TP tunneling

Explanation:
http://www.cisco.com/en/US/tech/tk175/tk819/technologies_white_paper09186a0080093bd2.shtml
In PPPoA architectures, the service destination can be reached in different ways. Some of the
most commonly deployed methods are:
Terminating PPP sessions at the service provider

L2TP Tunneling
Using SSG