Competitive Firms Hire Workers Until the Additional Benefit They Receive

Competitive firms hire workers until the additional benefit they receive from the last worker hired is equal to (i)
The additional cost of that worker.
(ii)
The wage paid to that worker.
(iii)
The marginal product of that worker.

A) (i) only
B) (iii) only
C) (i) and (ii) only
D) (ii) and (iii) only