A cylinder of internal radius a and external radius b = 1.3a is subjected to an internal pressure p. Determine for stress state (MPa) (or, de, tre) at inner surface. Take p = 20 MPa. (A) 20.0, 61.7,0 B) 20.0, 78.0, 0 0, 61.7, 0 0, 78.0, 0