When configuring a redundant trunk group (RTG) on an interface, which restriction would apply?

A.
The interface must be configured as a Layer 3 interface with an assigned IP address.

B.
The interface cannot be configured as a Layer 2 trunk.

C.
The gratuitous-ARP-reply must be disabled on the interface.

D.
Spanning Tree Protocol (STP) cannot be configured on the interface.