Match List-I with List-II and select the correct answer:

List-I	List-II
a. Gobar gas	1. CO + H2
b. Coal gas	2. CO + N2
c. Producer gas	3. CH4
d. Water gas	4. H2 + CH4 + CO

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

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

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

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

Answer: Option D