A block A of mass m, rests on a horizontal table. A light string connected to it passes over a frictionless pulley at the edge of table and from its other end another block B of mass m, is suspended. The coefficient of kinetic friction between the block and the table is When the block A is sliding on the table, the tension in the string is (a) (m-ukm)g (m +m) mm (1+uk)g (m +m) mm (1-Hk)g (m+m) (m+km)g (m+m) (c) (d)