A small block B of mass m is quickly placed on an inclined plane P, which makes an angle with a horizontal cart C, on which Pis rigidly fixed (see figure). The coefficient of friction between the block B and the plane C is u. When the cart stays stationary the block slides down. If the cart C is moving in the horizontal direction with acceleration a, the minimum value of a for which the block will remain static is tan 0- (a) g (cos-usin) 1- utan 0 + tan 0 (c) g lan 0+1 (d) g (-sin cos) (b) g