Which is not a guiding principle in key control system​

The discussion of the standards for selection of peanuts that will be used in m& ms and the placement of the m& m logo on the candies speaks to which building block of a sustainable competitive advantage:

In the market for lock washers, a perfectly competitive market, the current equilibrium price is $5 per box. washer king, one of the many producers of washers, has a daily short-run total cost given by tc = 190 + 0.20q + 0.0025q2, where q measures boxes of washers. washer king's corresponding marginal cost is mc = 0.20 + 0.005q. how many boxes of washers should washer king produce per day to maximize profit?

What common business mistake can cost you everything