Turpentine oil is flowing through a tube of length l and radius r. The pressure difference between the two ends of the tube is P. The viscosity of oil is given by η = P(r2-x2)/4vl where v,is the velocity of oil at a distance x from the axis of the tube. The dimensions of η are
(a) [M0L0T0]
(b) [MLT-1]
(c) [ML2T-2]
(d) [ML-1T-1]