The yield versus fertilizer input is shown in the graph. Consider the following statements based on this graph: I. Yield rate is zero at B and C. II. There is no yield with no fertilizer input. III. The yield is minimum at D. IV. The yield is neither minimum nor maximum at C. Which of the above statements are correct? The original graph is not available for this question.

1. (a)I, II and IV
2. (b)III and IV
3. (c)II and III
4. (d)I, III and IV