Use the Following to Answer Question 160 -Cindy Operates Birds-R-Us,a Small Store Manufacturing and Selling 100 Bird

Use the following to answer question 160: $$\begin{array}{l}\text { Table: Output and Marginal Cost }\\\begin{array} { l c } \hline \text { Output } & \text { Marginal Cost } \\\hline 1 & 15 \\2 & 10 \\3 & 5 \\4 & 8 \\5 & 12 \\6 & 20 \\\hline\end{array}\end{array}$$
-Cindy operates Birds-R-Us,a small store manufacturing and selling 100 bird feeders per month.Her monthly total fixed costs are $500,and her monthly total variable costs are $2 500.If for some reason Cindy's fixed cost fell to $400,then her _____ costs would _____.

A) average fixed;increase
B) average total;decrease
C) marginal;decrease
D) average variable;decrease