Your customer has selected switches that support 802.

For 802.3bz MultiGig Ethernet, which supports speeds of 2.5 Gbps and 5 Gbps over twisted-pair cabling, the recommended cabling standards vary based on the distance:

Cat-5e: Suitable for 2.5 Gbps up to 100 meters; 5 Gbps up to 55 meters

Cat-6: Suitable for 5 Gbps up to 55 meters

Cat-6a: Suitable for 10 Gbps up to 100 meters

Given that some cable runs will exceed 55 meters, Cat-6a is the most appropriate choice to ensure reliable MultiGig performance over longer distances.