Which of the following statements is incorrect?

a.

Britain has experienced rapid growth in the living standards and population since the Industrial Revolution.

b.

Law of diminishing average product of labour implies when land is fixed, average output cannot increase with each additional farmer working the land.

c.

According to the Malthusian model, sustained increase in income per capita is not sustainable.

d.

Isocost lines depict different combinations of factors of production, that give the same cost.