The correct answer is C. tendency.
A tendency is a natural inclination or predisposition towards a particular action or behavior. In this case, the person has a tendency to get into debt. This could be due to a number of factors, such as poor financial management, impulsive spending, or gambling addiction.
The other options are not as accurate. A characteristic is a distinguishing feature or quality of something. A quality is a high level of excellence or good performance. An aptitude is a natural ability or talent for something.
In this case, the person’s tendency to get into debt is not a distinguishing feature of them, nor is it a high level of excellence or good performance. It is simply a natural inclination or predisposition towards a particular action or behavior.