The technique used to ensure security in virtual private networks (VPNs) is:

A.
encapsulation.

B.
wrapping.

C.
transform.

D.
encryption.

Explanation:
Encapsulation, or tunneling, is a technique used to carry the traffic of one protocol over a network that does not support that protocol directly. The original packet is wrapped in another packet. The other choices are not security techniques specific to VPNs.