WAEC Agricultural Science 2009 Question 16

Which of the following statements indicate advantages of sub-surface irrigation?
I. Low operating cost once established
II. Does not disturb the movement of implements
III. Permits efficient use of water
IV. Easily floods the field

1. A.I, II and III only
2. B.II, III and IV only
3. C.I, III and IV only
4. D.I, II, III and IV