Assertion $(A)$: $A$ room can be cooled by opening the door of a refrigerator in it.
Reason $(R)$: Heat always flows from a body at higher temperature to a body at lower temperature.

• A
  $(A)$ and $(R)$ are true and $(R)$ is the correct explanation of $(A)$.
• B
  $(A)$ and $(R)$ are true and $(R)$ is not the correct explanation of $(A)$.
• C
  $(A)$ is true but $(R)$ is false.
• D
  $(A)$ is false but $(R)$ is true.