The figure shown blocks \( A \) and \( B \) are of mass \( 2 \mathr...

The figure shown blocks \( A \) and \( B \) are of mass \( 2 \mathrm{~kg} \) and \( 8 \mathrm{~kg} \) and they are connected through strings to a spring connected to ground. The blocks are in equilibrium. \( \left(g=10 \mathrm{~m} / \mathrm{s}^{2}\right) \)
- Now the block A is pulled downwards by a force gradually increasing to \( 20 \mathrm{~N} \). The new elongation of spring is :-
(A) \( 2 \mathrm{~cm} \)
(B) \( 4 \mathrm{~cm} \)
(C) \( 20 \mathrm{~cm} \)
(D) \( 40 \mathrm{~cm} \)