Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.
Reason R: The sand used in slow sand filters is finer than that in rapid sand filters
Select your answer based on the coding system given below:

A. Both A and R is true and R is the correct explanation of A

B. Both A and R is true but R is not the correct explanation of A

C. A is true but R is false

D. A is false but R is true

Answer: Option A