In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices. (a) Assertion and reason both are correct and reason is correct explanation of assertion. : (b) Assertion and reason both are wrong statements. (c) Assertion is correct statement but reason is wrong statement. (d) Assertion is wrong statement but reason is correct statement. (e) Assertion and reason both are correct statements but reasson is not correct explanation of assertion. Assertion : Formaldehyde is a planar molecule. Reason : It contains `sp^2` hybridised carbon atom.