What is the purpose of the autonomous-system {autonomous-system-number} command?

What is the purpose of the autonomous-system {autonomous-system-number} command?
A . It sets the EIGRP autonomous system number in a VR
C . It sets the BGP autonomous system number in a VR
E . It sets the global EIGRP autonomous system number.
F . It sets the global BGP autonomous system number.

Answer: A

Explanation:

To configure the autonomous-system number for an Enhanced Interior Gateway Routing Protocol (EIGRP) routing process to run within a VPN routing and forwarding (VRF) instance, use the autonomous-system command in address-family configuration mode. To remove the autonomous-system for an EIGRP routing process from within a VPN VRF instance, use the no form of this command. Autonomous-system autonomous-system-number no autonomous-system autonomous-system-number

Reference: http://www.cisco.com/c/en/us/td/docs/ios/iproute_eigrp/command/reference/ire_book/ ire_a1.html#wp1062796