Answer:
C. 12 feet
Explanation:
We have been given that Carlos swam to the bottom of a pool that is 12 feet deep. 
Since Carlos swam to the bottom of the pool, so his elevation will be 
 feet with respect to surface.
 feet with respect to surface.
The opposite of Carlos elevation relative to the surface would be opposite of 
 feet that is
 feet that is 
 feet.
 feet.
 feet
 feet
Therefore, the opposite of Carlos elevation relative to the surface is 12 feet.