question_answer

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)