$[4$ points$]$ Suppose that a uniform thin rod of length $0\mathrm{.}82$ m is pivoted on the floor on one end. Initially it is standing upright. When let go$,$ the rod falls by rotating about the pivot. At some instant during the fall, the tangential acceleration of the free end is $g($the acceleration of gravity$).$ What is the angle of the rod measured from the floor at that instant?

A$.$ At any angle as the tangential acceleration of the end is always $g.$

B$.71$

C$.48$

D$.80$

E$.85$