The marginal physical product of labour is defined as

Select one:

a.the change in firm revenues resulting from the employment of one more worker,ceteris paribus.

b.the change in output resulting from the employment of one more worker,ceteris paribus.

c.the change in firm costs resulting from the employment of one more worker,ceteris paribus.

d.the change in average output per worker when an additional worker is employed,ceteris paribus.