Let the tensile force of rope AO and rope BO be f, take point o as the research object, and point o is subjected to gravity mg,

The supporting force F 1 and the force f 1 of the rod.

According to the equilibrium condition

F=mgtan30

F is decomposed as shown in Figure 2.

Then the pulling force exerted by AO is F2=22F=66mg.

So choose d