Consider the following statements related to all – air conditioning system:
1. All air system uses air as heating or cooling fluid.
2. When hot air is circulated through rooms, dehumidification is necessary to control relative humidity.
3. Return air ducts are required for recirculation.
Which of the statements given above are correct?
(a) 1, 2 and 3 (b) 1 and 2 only
(c) 1 and 3 only (d) 2 and 3 only