Match the followings:
| A. Fixed-ratio schedule | I. Reinforcement is given after unpredictable number of responses. |
| B. Variable-ratio schedule | II. Reinforcement is given after a fixed time period. |
| C. Fixed-interval schedule | III. Reinforcement is given after a fixed number of responses. |
| D. Variable-interval schedule | IV. Reinforcement is given after unpredictable time intervals. |
1
A-I, B-II, C-III, D-IV
2
A-II, B-III, C-IV, D-I
3
A-III, B-I, C-II, D-IV
4
A-IV, B-III, C-II, D-I