Two statements are given , one labelled ' Assertion ' (A) and the other 'Reason ' (R) . Select the correct option with regard to the statements . Assertion (A) :Plains have denser population as compared to hilly regions . Reason (R) : People avoid living in regions with extreme climate . a) Both A and R are true , and R is the correct explanation of A . b) Both A and R are true , and R is the correct explanation of A . c) A is true , but R is false . d) A is false ,but R is true .​