Refer to the exhibit. An engineer connects a Cisco ACI fabric to two different Cisco Nexus 9000 Series Switches. The fabric must be configured to ensure a loop-free topology and N9K1 must be…

STP is not run on ports between ACI leaf and spine switches; ACI uses different mechanisms like ECMP for internal loop prevention.

BPDU Guard shuts down an interface upon receiving BPDUs and is typically used on access ports to prevent unauthorized STP participation, not for inter-switch links in this context.

Cisco Discovery Protocol (CDP) is a Layer 2 protocol used for discovering information about directly connected Cisco devices, not for loop prevention or STP management.

Multi-Chassis Protection (MCP) is a critical Cisco ACI feature designed to prevent Layer 2 loops and handle Spanning Tree Protocol (STP) BPDUs when the ACI fabric connects to external switches, particularly in vPC+ or multi-homed scenarios. Activating MCP intelligently processes or drops BPDUs on the external facing ports, allowing the external switches to elect a root bridge while maintaining ACI's loop-free forwarding design.