For a shaft under bending and torsion effect, Ma $=60$Nm$,$ Ta$-40$Nm$,$ Mm $=50$Nm and Tm $=30$ Nm$.$ In addition, it is assumed that Su$=700$Mpa and Sy$=560$MP and the fully corrected strength limit Se is $210$MPa. Kf $=2\mathrm{.}2$ and Kfs $=1\mathrm{.}8.$ Calculate the safe minimum shaft diameter for each option below, with the design coefficient being $2.$ for a$)$ DE$-$ Gerber Criterionb$)$ DE$-$ Elliptic Criterionc$)$ DE$-$Soderberg Criteriond$)$ DE$-$Goodman. criterion