What is the objective function?
a) Minimizing shipping cost = $20 + $15 + $18 + $23 + $20 + $25 + $30 + $25 + $15 + $40 + $15 + $20 + $25 + $30
b) Minimizing shipping cost = $20XNM + $15XNR + $18XKM + $23XKR + $20XCM + $25XCR + $30XMA + $25XMH + $15XMD + $40XML + $15XRA + $20XRH + $25XRD + $30XRL
c) Maximizing shipping cost = $20XNM + $15XNR + $18XKM + $23XKR + $20XCM + $25XCR + $30XMA + $25XMH + $15XMD + $40XML + $15XRA + $20XRH + $25XRD + $30XRL
d) Minimizing shipping cost = XNM + XNR + XKM + XKR + XCM + XCR + XMA + XMH + XMD + XML + XRA + XRH + XRD + $XRL