A cylinder of mass $m$ rests in a carriage shown. The maximum acceleration of carriage so that the cylinder does not loose contact at $B$ is :
(a) $3.66 \mathrm{~m} / \mathrm{s}^{2}$
(b) $10 \mathrm{~m} / \mathrm{s}^{2}$
(c) $45 \mathrm{~m} / \mathrm{s}^{2}$
(d) $8 \mathrm{~m} / \mathrm{s}^{2}$