To determine whether it is possible to mix 100BaseTX and 1000BaseT4 on a single network segment, we need to understand the compatibility between these two technologies.

100BaseTX and 1000BaseT4 are Ethernet standards that specify the maximum data transfer rate and the type of cabling used.

100BaseTX operates at a maximum speed of 100 Mbps (Megabits per second) and uses twisted pair copper cables. It uses two pairs of wires for transmitting and receiving data.

1000BaseT4, on the other hand, operates at a maximum speed of 1000 Mbps (1 Gbps) and also uses twisted pair copper cables. However, it uses all four pairs of wires for transmitting and receiving data.

Based on this information, it is not possible to mix 100BaseTX and 1000BaseT4 on a single network segment. The two standards have different data transfer rates and use different wire configurations. Mixing them on the same segment would result in compatibility issues and unreliable network performance.

Therefore, the correct answer is:

B. False