Assertion (A): The resultant unbalanced force at any instant would be the minimum when half of weight fixed opposite the crank, but the common practice is to balanced two-thirds of the reciprocating parts.
Reason (R): Unbalanced force along the line of stroke is more harmful than that in a direction perpendicular to it.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not a correct explanation of A
(c) A is true but R is false
(d) A is false but R is true