Question $6\mathrm{.}11-$ A cantilever $AB$ is being propped by a cable $BC,$ as shown in Fig. $6\mathrm{.}13.$ The tension in the cable is $9kN.$ If counterclockwise $($ccw$)$ moment is considered positive, the moment the force exerts about support $A(kN-m)$ is most nearly:

A$.49$

B$.-45$

C$.81$

D$.-81$

Fig. $6\mathrm{.}13$