Can you help me with this multiple-choice question on static equilibrium?

I think it is about 6.9N.This is because block B has a horizontal force in the form of Tsin(40).Here,T is equal to W of block C(if pulley is of negligible m).This force is counter acted by the frictional force,which keeps it in equilibrium.This is about 6.42787N,approximately 6.5N.So,may be it can hold it until 6.9N(the closest).