Adjoining figure shows two blocks A and B pushed against the wall with a force \( \mathrm{F} \)....

Adjoining figure shows two blocks A and B pushed against the wall with a force \( \mathrm{F} \). The wall is smooth but the surfaces in contact of \( \mathrm{A} \) and \( \mathrm{B} \) are rough. Which of the following is true for the system of blocks to be at rest against the wall ?
(1) Fshould be be more than the weight of A and \( \mathrm{B} \)
(2) \( F \) should be equal to the weight of \( A \) and \( B \)
(3) \( F \) should be less than the weight of \( A \) and \( B \)
(4) system cannot be in equilibrium
\( \mathrm{P} \)
W