Correct Answer: frugal

Solution : The correct choice is the third option.

In the context of budgeting and making the most of resources, frugal is the most suitable term. Being frugal implies being careful and economical in spending, which aligns with the idea of efficiently managing a budget.

The meanings of the other options are as follows:

• Miser refers to someone who hoards wealth and is usually not willing to spend money, but it doesn't necessarily convey the sense of making the most out of a budget.
• Lethargic and gloomy are unrelated to the idea of budgeting or managing resources efficiently.