Three blocks \( A, B \) and \( C \) of masses \( 4 \mathrm{~kg}, 2 \mathrm{~kg} \) and \( 1 \mat...

Three blocks \( A, B \) and \( C \) of masses \( 4 \mathrm{~kg}, 2 \mathrm{~kg} \) and \( 1 \mathrm{~kg} \) respectively, are in contact on a frictionless surface (Fig. III-3). If a force of \( 14 \mathrm{~N} \) is applied on the \( 4 \mathrm{~kg} \) block, then the contact force between \( A \) and \( B \) is :
Figure III-3
(A) \( 6 \mathrm{~N} \)
(B) \( 8 \mathrm{~N} \)
(C) \( 18 \mathrm{~N} \)
(D) \( 2 \mathrm{~N} \)