Table 13-4
the Following Table Shows the Production Possibilities for Charles

Table 13-4
The following table shows the production possibilities for Charles' math tutoring company.
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$$\begin{array} { | c | c | } \hline \begin{array} { c } \text { Labor } \\\text { (Number of tutors) }\end{array} & \begin{array} { c } \text { Output } \\\text { (Number of students } \\\text { tutored per week) }\end{array} \\\hline 0 & 0 \\\hline 1 & 20 \\\hline 2 & 45 \\\hline 3 & 60 \\\hline 4 & 70 \\\hline\end{array}$$ ​
-Refer to Table 13-4. Suppose that Charles's math tutoring company has a fixed cost of $50 per month for his cell phone. Each worker costs Charles $60 per day. As output increases from 45 to 70 students, Charles's total cost curve

A) increases but gets flatter.
B) increases and gets steeper.
C) decreases and gets flatter.
D) decreases but gets steeper.