If a unit of labour costs 3 times to that of a unit of capital, then in the long run, ________.
1) The firm will hire more capital and less labour.
2) The marginal product of labour equals to 1/3 of the marginal product of capital.
3) The marginal product of labour equals to 3 times of the marginal product of capital.
4) The firm will hire more labour and less capital.