Assertion: A spring of force constant `k` is cut into two pieces having lengths in the ratio 1 : 2. The force constant of series combination of the two parts is `2k'/'3`.
Reason: The spring connected in series are represented by `k= k_1+ k_2`.
Options:
(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 the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.