For several weeks, allen had to clean the men's restroom at the restaurant where he worked. the task always made him nauseated. he has since gone on to better things, but still cannot walk by the door to a men's restroom without becoming slightly queasy. for allen, the door to the men's room has become a(n)

For Allen, the door to the men's room has become a "conditioned stimulus".

In classical conditioning, the conditioned stimulus refers to a formerly neutral stimulus that, which becomes conditioned stimulus when it is associated or linked to the unconditioned stimulus.

This is also known in Pavlov's Classical conditioning, Ivan Pavlov was the one who first found the procedure of classical conditioning in his experiments.

marginal cost is a microeconomic measure that us to evaluate the extent to which the level of production of a good is sustainable in accounting, that is, to how many quantities the company plans to profit from the production of the good.

the concept of marginal cost is simple, it means the cost of producing one more item. for example, in the case of pies, the marginal cost is the cost of producing one more pie than those that have already been produced.

it is important to understand that productive activity influences marginal cost. the marginal cost of some goods can be very high, while others may be insignificant. for example, the marginal cost of producing an extra plane is very high. already the marginal cost of a water company to provide 1l more water is derisory.

in the case of pies, the cost involves the inputs, the labor and the fixed cost, which involves the fixed space of the bakery. the level of production initially has the marginal cost decreasing because there is space and manpower available. however, to produce more you have to hire more workers and buy more inputs. if physical space is limited, workers will conflict with places, inputs and their productivity will decrease, meaning there is an optimum point of production for each level of space and manpower. from this point on, the productivity of the workers will be getting smaller because of lack of space, so that the marginal cost of producing one more pie will be increasing. so, although you have not posted the chart, but if you have the answer, you can see that my explanation goes according to the marginal cost curve that will increase from the 4th pie, answer (c).