When it comes to the best operating level, all of the above are correct.
The best operating level is where all resources are being utilized effectively and marginal revenue is equal to marginal cost. If there resources are not being utilized effectively, the following will happen:
At the best operating level however, average cost will be at a minimum because the goods are being used effectively and efficiently.
In conclusion, it is best for a business when they operate at an efficient operating level.
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