how to understand the 2nd and 3rd one well?

the difference between min the cost per unit of output and use the smallest total quantity of all resources

I cannot understand the table

MC Qu. 76 Enterprise managers and workers in the Sovie...
Enterprise managers and workers in the Soviet Union often resisted innovations in production methods because:
A. production targets were often increased when innovation occurred.
B. there was a chronic shortage of computers.
C. workers could not be reallocated geographically.
D. innovations ordinarily increased dependence on world markets.
Students asked why the answer A is correct?
My Answer:
Under command system, personal rewards was based on the fixed quantitive targets set up by central government, instead of qualitive targets.
The managers who were working on the factories had no incentive to innovate or work additional hours.
Innovation would definitely improve the quality of products and service produced by the factories.
But in the meanwhile, the managers and workers would definitely have to work more hours without any additional rewards.
That was why they resisted innovations.
Regards
David Lin

@DlinKean
In order to derive a market demand curve from individuals' demand curves, we add up the:
Various prices that each buyer is willing and able to pay
→ Various individuals' quantities demanded at each price level
Total number of buyers in the market at each time period
Incomes of all buyers, assuming that their tastes remain constant

Does China have a mixed economy right now？？？