An unotched rotating circular rod is subjected to a fluctuating bending load that causes the bending stress to vary between -5 ksi and 25 ksi. If the modified endurance limit of the rod is 42 ksi, and the yield strength and the ultimate strength of the material of the rod are 120 ksi and 180 ksi respectively, find the design factor for high-cycle fatigue life of a 100,000 load cycles using (a) Modified Goodman, (b) Soderberg criteria, (c) Gerber criteria and (d) the ASME-Elliptic criteria.