The Following Data Pertains to Activity and Costs for Two

The following data pertains to activity and costs for two months: $$\begin{array} { | l | l | l | } \hline & \text { June } & \text { July } \\\hline \text { Activity level in units } & 10,000 & 20,000 \\\hline & & \\\hline \text { Variable costs } & \$ 20,000 & \$ ? \\\hline \text { Fixed costs } & 15,000 & ? \\\hline \text { Mixed costs } & 10,000 & ? \\\hline \text { Total costs } & \$ 45,000 & \$ 70,000 \\\hline\end{array}$$ Assuming that these activity levels are within the relevant range, the mixed costs for July were?

A) $40,000.
B) $10,000.
C) $35,000.
D) $15,000.