For the state of plane stress shown, the components of normal and shear stresses are given in terms of stress o and unknown constants m and n. If the normal and shear components of stress on a 45 plane are 20 and zero, the values of m and n would be: 20 no (A) m = 1, n = 2 (C) m = 1, n = 1 mo 45 (B) m=2, n = 1 (D) m = 2, n = 2