a
(a) If velocities of water at entry and exit points are \(v_1 and v_2\), then according to equation of continuity, \({A_1}{v_1} = {A_2}{v_2}\)==> \(\frac{{{v_1}}}{{{v_2}}} = \frac{{{A_2}}}{{{A_1}}} = {\left( {\frac{{{r_2}}}{{{r_1}}}} \right)^2} = {\left( {\frac{2}{3}} \right)^2} = \frac{4}{9}\)