A long horizontal rod has a bead which can slide along its length and initially placed at a
distance L from one end A of the rod. The rod is set in angular motion about A with constant angular acceleration `alpha.` if the coefficient of friction between the rod and the bead is `mu`, and gravity is neglected, then the time after which the bead starts slipping is
A. `sqrt(mu/alpha)`
B. `mu/sqrt(alpha)`
C. `1/sqrt(mualpha)`
D. Infinitesimal