An L-shaped object, made of thin rods of uniform mass density, is suspended with a string as shown in figure. If AB = BC, and the angle made by AB with downward vertical is $\theta$, then :

(1) $\tan\theta={2\over\sqrt{3}}$

(2) $\tan\theta={1\over3}$

(3) $\tan\theta={1\over2}$

(4) $\tan\theta={1\over2\sqrt{3}}$