Answer: a. the depth of the water table increases
Step-by-step explanation: Yikes! It seems like people have been misinterpreting the answer choices. The answer is NOT C! When we are referring to depth we are referring to the depth at which the water table is located, not the volume of water available! Answer choice A is correct because the depth at which we can find the water table INCREASES when the use of groundwater exceeds the rate of replenishment (The water level drops further into the depths of the Earth).
It is NOT B because overuse of groundwater does not necessarily increase the likelihood of the water table being polluted. Polluting groundwater does not necessarily lower the water table per say, but simply limits the amount of water that is safe for use.
The answer is NOT C because as stated earlier, we are referring to the level at which the water table is located. If the depth at which the water table is FOUND decreases it is actually rising towards the surface. Essentially, if you answer C, you are stating that overuse of groundwater is increasing the amount of groundwater available. Doesn't make much sense right?
D is NOT correct because using groundwater faster than natural processes can replenish it will create a deficit, in which the water table will recede as a result. Think about it this way, if you spring a major leak in your aboveground pool and require rainwater to replenish any losses (Don't worry you still work to maintain proper chlorine levels), the water level will still go down right? The same thing happens in this scenario, making answer choice D's statement false. Water is not an infinite resource ya know!
Hope this helps to clear up any misconceptions. The person who created the question used confusing wording for the answers. I saw a lot of people putting C as the answer for most posts (And people gave them five stars!!) so I thought I'd clear things up :))))