a$)$ The use case model drives the entire OOAD process. Clearly explain the implication of this statement.

b$)$ Draw a use case diagram the following scenario

During the enrollment of modules at a college, a student completes a module registration form. The student selects units from the course catalogue and enters them in the form. Each module has a maximum capacity for students. The administrator then checks the form and ascertains the availability of modules. If there is still space in a module, the administrator registers student on the module. If ther is no space the student is advised to select another module.