Which of the following sets consists of only the core features of a mobile or computing device?

A$.$ Small form factor, mobile operating system, wireless data network interface for internet access, global positioning system $($GPS$),$ local nonremovable data storage

B$.$ Small form factor, mobile operating system, microphone and$/$or digital camera, app stores, local non$-$removable data storage

C$.$ Small form factor, mobile operating system, wireless data network interface internet access, app stores, removable storage media

D$.$ Small form factor, mobile operating system, wireless data network interface for internet access, app stores, local nonremovable data storage