Mr Khanna had a pond in his garden, filled with all kinds of aquatic plants. He wanted to prevent mosquitoes from breeding in the pond without harming the plants in any way. He could _______. (i) Add salt into the water (ii) Add some goldfish into the pond (iii) Spray a film of oil on the surface of the pond

• A.  (i) only                       
• B.  (ii) only          
• C.         (iii) only         
• D.         (i), (ii) and (iii)