Solution:

The best option is (a).

By evaluating your monthly budget, you can learn how to keep your personal spending under control.

A monthly budget helps you to control and manage spending. It helps to make sure that your hard earned money is to put in the highest priority need and best purpose. If you are over spending, then your monthly budget becomes negative. Hence, it makes you sure how much you are spending and where you are spending, if you are really in a need of it you will spend money else you will stop spending money on it. By controlling on the spending you can maximize saving and investment.

Conclusion:

Hence, by evaluating your monthly budget, you can learn how to keep your personal spending under control.