A thick open ended cylinder as shown in the figure, is made of a material with permissible normal and shear stresses 200 MPa an(d) 100 MPa respectively. The ratio of permissible pressure based on the normal and shear stress is.
(a) 9 / 5 (b) 8 / 5
(c) 7 / 5 (d) 4 / 5