The amount of labour hired depends on the

The amount of labor hired depends on the marginal productivity of labor. Marginal productivity of labor refers to the amount of output produced by an additional unit of labor. In other words, a firm will continue to hire labor until the cost of an additional unit of labor equals the additional revenue generated by that unit. Therefore, if the marginal productivity of labor is high, a firm will hire more labor, and if it is low, a firm will hire less labor. The other options listed (number of skilled labor available, skill of labor, and price of the inputs) can all influence the marginal productivity of labor and therefore impact the amount of labor hired, but they are not the sole determining factor.