WAEC Economics 2019 Question 14

Use the table below (Table I) to answer the question.
Units of quantity consumed | Total Utility | Marginal Utility
0 | - | -
1 | 10 | 10
2 | 15 | 5
3 | 17 | 2
4 | 18 | 1
5 | 18 | 0
Table I illustrates the law of

1. A.diminishing returns
2. B.diminishing marginal productivity.
3. C.diminishing marginal utility.
4. D.variable proportion.