A cable in a network is only capable of 100 Mbps maximum speed. What type of cable is this?

Cat 5 UTP can transmit data at up to 100 Mbps over a 100-meter distance. Cat 5e has a data rate of 1 Gbps. Cat 6 and later can handle 10 Gbps. Single mode fiber optic cable is a very fast form of fiber optic cable.