If $\Delta$ TC Represents the Change in Total Cost $\Delta$ W the Change in the Wage Rate

If $\Delta$ TC represents the change in total cost, $\Delta$ w the change in the wage rate, $\Delta$ TFC the change in total fixed cost, $\Delta$ q the change in output,and $\Delta$ AC the change in average cost,the marginal cost of the firm can be defined as:

A) $\Delta$ TC/ $\Delta$ w.
B) $\Delta$ TFC/ $\Delta$ q.
C) $\Delta$ AC/ $\Delta$ q.
D) $\Delta$ TC/ $\Delta$ q.