Assertion (A) Large cold storage plants use ammonia as a refrigerant, while domestic refrigerants use chloro-fluorocarbons. Reason (R) Ammonia can be liquefied at low pressure and ambient temperature.

• A. Both A and R are correct and R is the correct explanation of A
• B. Both A and R are correct but R and R is not the correct explanation of A.
• C. A is right but R is wrong
• D. A is wrong but R is right