A compound cylinder with inner radius 5 cm and outer radius 7 cm is made by shrinking one cylinder over the other cylinder. The junction radius is 6 cm and the junction pressure is 11 kg/cm2. The maximum hoop stress developed in the inner cylinder is
(a) 36 kgf/cm2 compression
(b) 36 kgf/cm2 tension
(c) 72 kgf/cm2 compression
(d) 72 kgf/cm2 tension