In sulphuric acid plants dry air is used for burning of sulphur. Air is dried in contact with concentrated Sulphuric acid. Moisture diffuses through a layer of air, reaches the surface and gets absorbed in it. Here air is said to be non-diffusing were as moisture is diffusing. Which of the following statements are correct?

• A. Moisture has a source and a sink whereas dry air has a source but no sink
• B. Moisture as well as dry air have a sink
• C. Moisture has a source but no sink whereas dry air has a source as well as sink
• D. Moisture as well as dry sir have no sink