Given a market wage of W$*,$ what is the expression for the market quantity demanded of labour Nm$?$

a$.$

The vertical summation of all of the Nf curves, where Nf is the firm's quantity demanded of labour at W$*.$

b$.$

The percent change in Nm divided by the percent change in the wage.

c$.$

The sum of all of the values of Nf$,$ where Nf is the firm's quantity demanded of labour at W$*.$

d$.$

It cannot be derived, as it has to be given.

e$.$

The product all of the values of Nf$,$ where Nf is the firm's quantity demanded of labour at W$*.$