Which of the following is true regarding 'grounded theory' research?

A. Axial coding is the process of relating sub-categories to a category.

B. It includes continuous comparative analysis of cases.

C. Selective coding continues the axial coding at a higher level of abstraction.

D. The size of sample is determined by the theoretical saturation of categories.

E. It is a substitute of experimental research.

Choose the correct answer from the options given below: