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

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

A is true but R is false.

A is false but R is true.

excessive negative head

mud ball formation

higher turbidity in the effluent

low temperature

0.2 to 0.4

0.4 to 1.0

2 to 4

5 to 7

24 - 48 hours

10-12 days

2-3 months

1-2 year

less than that of slow sand filters

in between the filtration rate of slow sand filters and rapid sand filters

greater than that of rapid sand filters

equal to that of slow sand filters