What would be the best reason for selecting L2TP as a tunnel protocol for a VPN Client?

What would be the best reason for selecting L2TP as a tunnel protocol for a VPN Client?

A.
L2TP uses TCP as a lower level protocol so the transmissions are connected oriented, resulting in more reliable delivery.

B.
L2TP uses PPP so address allocation and authentication is built into the protocol instead of relying on IPSec
extended functions, like mode config and a-auth.

C.
L2TP does not allow the use of wildcard pre-shared keys, which is not as secure as some other methods.

D.
L2TP has less overhead than GRE.