question_answer

Greenhouse gases are responsible for global warming. They enter our atmosphere either naturally or anthropogenically. Match column I (containing greenhouse gases) with column II (containing their source) and select the correct option from the given codes.

Column I	Column II
1. Carbon dioxide	a. Livestock farming
2. Methane	b. Use of air conditioner
3. CFCs	c. Fossil fuel combustion
4. Nitrous oxide	d. Cement production

A)  1-d, 2-a, 3-b, 4-c

B)  1-a, 2-d, 3-c, 4-b

C)  1-c, 2-b, 3-d, 4-a

D)  1-b, 2-d, 3-a, 4-c