When are packets processed by an inbound access list?

A.
Before they are routed to an outbound interface

B.
After they are routed to an outbound interface

C.
Before and after they are routed to an outbound interface

D.
After they are routed to an outbound interface but before being placed in the outbound queue

Explanation:
For inbound ACL, before the router forwards groups to other interface, the router will compare group and interface ACL. ACL statement will process in top-down order, until a match item is found; the follow-up statement will no longer be handled. If no matching item is found in ACL, groups will be discarded (implicit refusal).

When a packet is received on an interface with an inbound access list configured, the packets are matched against the access list to determine if they should be permitted or denied. After this check, the packets are processed by the routing function. The access list check is always done first.