Q.) Locus of the point P for which OP represents a vector with direction cosine cos α = 1/2 (where O is the origin) is
[A]a circle parallel to the y-z plane with centre on the x-axis
[B]a cone concentric with the positive x-axis having vertex at the origin and the slant height equal to the magnitude of the vector
[C]a ray emanating from the origin and making an angle of 60° with the x-axis
[D]a disc parallel to the y-z plane with centre on the x-axis and radius equal to |OP| sin 60°
