In an engineering component made of ASTM 30 Gray Cast Iron (use Shigley's tables), the critical element is subjected to the stress components σ x  =9ksi,σ y  =−15ksi,σ z  =6ksi, τ xy  =12ksi,τ yz  =τ xz  =0. Determine the safety factors based on (a) MNST, (b) CMT, and (c) MMT.