$7.$ MRS and utility maximization

Suppose your classmate Becky loves to eat dessert$$so much so that she allocates her entire weekly budget to peach cobbler and pie. The price of one bowl of peach cobbler is $$1\mathrm{.}75,$ and the price of a piece of rhubarb pie is $$5\mathrm{.}25.$ At her current level of consumption, Becky's marginal rate of substitution $($MRS$)$ of peach cobbler for pie is $3.$ In other words, Becky is willing to sacrifice three bowls of peach cobbler for one piece of pie per week.

Does Becky's current consumption bundle maximize her utility? That is$,$ does it make her as well off as possible? If not, how should she change it to maximize her utility?

Becky could increase her utility by buying less peach cobbler and more pie per week.

Becky's current bundle maximizes her utility, and she should keep it unchanged.

Becky could increase her