If any problems involving circular motion, which way does the tangential speed vector point?

It is always drawn along the tangent of the circle at the point where we need the velocity.

Explanation:

When object is revolving in circular path in either clockwise of counterclockwise direction then in that case the direction of velocity is always determined by making a tangent at the position on the circle where we wish to find the velocity

Direction of tangent is always by sense of rotation either clockwise or counter clockwise.

the answer is a. at the equator