Listed Below Are Several Possible Combinations for Producing 10,000 Units

Listed below are several possible combinations for producing 10,000 units of a lamp:
$\begin{array}{llll}&\text { Materials } &\text { Labour } &\text { Power }\\\text {Unit input prices}&\$ 16 \text { per kg } & \$ 20 \text { per hr. } &\$ 4 \text { per kwh}\\\text { Input combinations:}\\\text { A } & 190 \mathrm{~kg} & 380 \mathrm{hrs} . & 1,520 \mathrm{kwh} \\\text { B } & 180 \mathrm{~kg} & 360 \mathrm{hrs} . & 1,440 \mathrm{kwh} \\\text { C } & 200 \mathrm{~kg} & 400 \mathrm{hrs} . & 1,000 \mathrm{kwh} \\\text { D } & 220 \mathrm{~kg} & 440 \mathrm{hrs} . & 1,100 \mathrm{kwh}\end{array}$
a.Identify the technically efficient input combinations.Explain your choices.
b.Which of the technically efficient input combinations should be used? Explain.