Many young people complete their education and find it impossible to afford a new home despite having a well-paying job, yet their parents had a very different experience. This is an example of mobility.

A. upward social mobility
B. horizontal social mobility
C. downward social mobility
D. vertical social mobility

D. vertical social mobility

Explanation:

Social mobility is the situation whereby the  social status of a given particular region tends to move in either vertically or horizontally. This mobility changes determines the situation in which the citizens standard of living in a place tilts towards to.

In the case scenario given above, the inability of the young people to afford new homes despite having a well paying job in contrast to thier parents experience few years ago shows vertical social mobility. This means that the standard of living has astronomically increased upwardly when compared to few years ago.

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).