Groundwater is in danger partially due to

A. sinkhole formation.

B. the building of dams.

C. a slow recharge rate.

D. infiltration by acidic water.

Option A) sinkhole formation.

Explanation:

A sinkhole refers to any dug-out or depressed area of land where human

or animal waste (excreta) are deposited.

Now, since these wastes contains water and are biodegradable by microorganisms, the fecal matter could be infected and in turns infect groundwater.

The contaminated-groundwater poses danger due to disease-causing organisms like

- vibrio cholerae, causing cholera

- Salmonella typhi, causing typhoid outbreak present, and also reduces volume of suitable drinking water in the community

Thus, the answer is sinkhole formation

because of