How does TDMA increase the network capacity over what FDMA can provide?

Choice $1$ of $4$: It allows for the interoperability of different standards.

Choice $2$ of $4$: It allows some users to text rather than call, thereby increasing the number that can use the network simultaneously.

Choice $3$ of $4$: It allows each frequency channel to service multiple users by separating them in time.

Choice $4$ of $4$: It allows each frequency channel to service multiple users by dividing the channel into smaller frequencies.