Consider the following statements.
1. Limestone, chalk and marble are different forms of calcium carbonate.
2. When pH of rain water is less than 5.6, it is called acid rain.
3. Human body works with in the pH range of 7.0 to 7.8.
Which of the statements given above are correct?

A. 1 and 2

B. 1 and 3

C. 2 and 3

D. 1, 2 and 3

Answer: Option D