Explain the following statements:

( i) Profit is the rent for exceptional ability of an entrepreneur (Walker).

( ii) Profits arise only in a dynamic world (J.B. Clark).

( iii) Profit is a reward for risk bearing (F.B. Hawley).

( iv) Profit is a return to uncertainty bearing (F.H. Knight).

v) Profit is reward for innovations (J.A. Schumpeter).