The value is the number of time units a programmed timer is programmed to count before timed contacts change state.

Preset Value

Explanation:

The preset value is actually the number of time unit a programmed timer is being programmed for counting before the timed contact changes the state.  And hence, its certainly the preset value the correct answer above. And remember the clock rate is defined by step function the time taken to reach 0 value from 1 is one time unit. Also, its the timed contact that changes the state, after the preset value is surpassed. And that is why its the timed contact, which means with fixed preset value.