Which of the Following Is True? at a Given Quantity

Which of the following is true? At a given quantity of employment,if the
i.value of marginal product of a high-skill worker is $35 and the value of marginal product of a low-skill worker is $10,the value of marginal product of the skill is $25.
ii.value of marginal product of a high-skill worker is $35 and the value of marginal product of a low-skill worker is $10,the cost of acquiring the skill is $25.
iii.value of marginal product of a skill is $25,then the wage rate must be $25.

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