A round shaft of diameter ‘d’ and length ‘l’ fixed at both ends ‘A’ and ‘B’, is subjected to a twisting moment ‘T’ at ‘C’ at a distance of ¼ from A (see figure). The torsional stresses in the parts AC and CB will be
(a) Equal
(b) In the ratio 1 : 3
(c) In the ratio 3 : 1
(d) Indeterminate