To determine the best descriptive classifier for buttons on a shirt from the options CL:B, CL:F, CL:D, and CL:G, we need to understand what each of these classifiers might represent in the context of buttons. However, without specific definitions for each classifier, it's challenging to choose the most appropriate one.
If you can provide more context or definitions for what each classifier represents, I would be able to assist you better in selecting the most suitable classifier for buttons on a shirt.