Arat in a skinner box is reinforced for the first bar press it makes after one minute has elapsed. the rat is on a schedule of reinforcement.
a) fixed-interval
b) fixed-ratio
c) variable-interval
d) variable-ratio

Fixed interval schedule

Explanation:

A fixed-interval schedule is used in ope-rant conditioning. It is used when the first action has been rewarded after some time elapsed. In this type of schedule, there are high chances of high respond near the end of the action.

But when the reinforcing has been given, instantly the response of the action gets slower. Ope-rant conditioning is conditioning that works on two called reinforcement and punishment. B.F Skinner was the first psychologist who introduced the ope-rant conditioning in which this two-term reinforcement and punishment were given.  

Thus here in the above statement, The rat in the Skinner box was reinforced in a fixed interval schedule.  

what words? are you talking about to complet what sentence