Refer to the exhibit.

A is correct because the automatically created trunk name is based on the MAC address of the FortiSwitch unit. When the FortiSwitch unit is replaced, the MAC address will change, but the trunk name will not change.

B is correct because CLAG-ICL is a manually configured link aggregation group. When the FortiSwitch unit is replaced, the CLAG-ICL configuration will need to be manually reconfigured on the new FortiSwitch unit.

The other options are incorrect. Option C is incorrect because the automatically created trunk name does not change when the FortiSwitch unit is replaced. Option D is incorrect because MCLAG-ICL is a manually configured link aggregation group and will not be automatically reconfigured when the FortiSwitch unit is replaced.

References:

Configuring link aggregation on FortiSwitches | FortiSwitch / FortiOS 7.0.4 - Fortinet Document Library

Managing FortiLink | FortiGate / FortiOS 7.0.4 - Fortinet Document Library

https://docs.fortinet.com/document/fortiswitch/7.0.8/devices-managed-by-fortios/173284/replacing-a-managed-fortiswitch-unit