Match the following columns:

Column I (Diseases)	Column II (Causes)
a. Ranikhet	1. Bacteria
b. Collibacillosis	2. Virus
c. Coccidiosis	3. Virus
d. Leucosis	4. Protozoan

A. a-2, b-1, c-4, d-3

B. a-1, b-2, c-3, d-4

C. a-1, b-3, c-2, d-4

D. a-4, b-1, c-2, d-3

Answer: Option A