From the question we are to determine Britta most likely task in preparing a budget.
First let's know what a budget is.
A budget is an estimation of revenue and expenses over a specified future period of time and is utilized by governments, businesses, and individuals. A budget is basically a financial plan for a defined period, normally a year that is known to greatly enhance the success of any financial undertaking.
So with the above explanation of what a budget is, Britta most likely task is to allot a set amount of money for her expenses.
Therefore the correct option is C, which is She is allotting a set amount of money for her expenses.