Jamie's Marginal Utility for Consuming Muffins and Doughnuts in Utils

Jamie's marginal utility for consuming muffins and doughnuts in utils are as follows.Jamie spends $4 for breakfast every morning,the price per muffin is $1.00 and the price per doughnut is $0.50. $$\begin{array} { | c | c | c | c | } \hline \text { Muffin/Day } & \begin{array} { c } \text { Marginal Utility } \\\text { per Muffin }\end{array} & \text { Doughnut/Day } & \begin{array} { c } \text { Marginal Utility } \\\text { per Doughnut }\end{array} \\\hline 1 & 45 & 2 & 20 \\\hline 2 & 30 & 4 & 15 \\\hline 3 & 25 & 6 & 10 \\\hline\end{array}$$
If Jamie consumes 3 muffins,what is Jamie's marginal utility per dollar from muffins?

A) 6.25
B) 7.5
C) 25
D) 15