Tex created a single$-$page Web app as a database tool for his small organization. However, as the organization has grown, the tool$$s use has become increasingly problematic. The data is saved in the same source code file as the program instructions, making it impossible to access the data while editing the program modules. Tex now has a $\_\_\_\_\_$ problem.

A$.$ data dependence

B$.$ data independence

C$.$ normalization

D$.$ serialization