A barometer tube reads $76\;cm$ of mercury. If the tube in gradually inclined at an angle of $60^{\circ}$ with vertical , keeping the open end immersed , in mercury reservoir, the length of the mercury column will be

Question

\[\begin {array} {1 1} (a)\;152\;cm \\ (b)\;90\;cm \\ (c)\;zero \\ (d)\;38\;cm \end {array}\]