The $100-1b$ door has its center of gravity at G$.$ Someone is pulling on the doorknob at point $C$ with a magnitude of $30lb$ along the line $CD.$ A second person is pulling with an unknown force $(C_x)$ on the other side of the doorknob directly in the negative $x-$direction. Determine the components of reaction at hinges A and $B$ if hinge $B$ resists only forces in the $x$ and $y$ directions and A resists forces in the $x,y,z$ directions. Also determine the force that the second person would need to pull with $($force $C_x)$ such that the system remains in equilibrium.