Refer to the exhibit.

Cisco troubleshooting logic supports Allow VLAN 100 between the switches as the required fix. In this question the symptoms point to HSRP, and the defect is best handled by correcting the exact control-plane or consistency condition. Nexus platforms can show interfaces or peers as configured while still refusing to forward traffic if a vPC Type-1 parameter, VLAN allowance, MTU, HSRP version, EVPN route, or routing attribute is wrong. Cisco methodology is to avoid broad resets unless the state machine is stuck; instead, correct the mismatched parameter and verify that the resulting operational state becomes stable. The other choices do not remove the root cause, or they modify a setting that is not used by the failing protocol exchange. After the change, the engineer should review the peer status, route or MAC table, and counters for drops or inconsistency messages. That sequence proves that the network fabric is fixed, not merely restarted.