Assertion (A) : Combustion of 16 g of methane gives 18g of water.  
Reason (R) : In the combustion  of methane, water is one of the products.

i)  Both A and R are true and R is the correct explanation of A. 
ii) A is true but R is false.      

iii) A is false but R is true  iv) Both A and R are false