Answer : 100 Base -Fx
A type of standard for implementing Fast Ethernet networks. 100BaseFX is a version of Fast Ethernet that is often used for wiring campus backbones. 100BaseFX is based on 802.3u, which is an extension of the 802.3 specifications of Project 802 developed by the IEEE. 100BaseFX and a related standard, 100BaseTX, are sometimes collectively referred to as 100BaseX.
Reference : Fast Ethernet