Answer:
A. Sleep
Step-by-step explanation:
A swimming pool is an artificial body of water that is typically used for recreational purposes such as swimming. It is usually designed in a rectangular form with an increasing depths as a swimmer proceeds further.
On the other hand, a bed is a structural piece of furniture that is designed to have a flat soft surface and used typically for sleeping.
Hence, the analogy is that while a pool is designed for swimming, a bed is designed for sleeping.
Therefore, Pool:swim :: bed:sleep