Firm X arranges its pay such that workers are underpaid early in their career but are overpaid later ...

Firm X arranges its pay such that workers are underpaid early in their career but are overpaid later in their career such that workers are, if they stay with the firm, on net better off. A necessary condition for this method of underpayments followed by overpayments to work is that
A) less motivated workers are more likely to stay with the firm and thus need more incentives to work hard.
B) workers discount the future with a high interest rate.
C) this sequencing of pay raises worker productivity.
D) supervising workers is cheap and effective.