In the context of the technologies developed to improve the efficiency and quality of digital communications, divides each channel into six time slots.

Time Division Multiple Access (TDMA)

Explanation:

Time Division Multiple Access (TDMA) is a digital cellular telephone communication technology which allow many users to share the same frequency without interference. It works by dividing a signal into different timeslots, and increasing the data carrying capacity.

Time Division Multiple Access (TDMA) is a complex technology since it requires accurate synchronization between the transmitter and the receiver. Again, TDMA is used in digital mobile radio systems. The individual mobile stations cyclically assign a frequency for the exclusive use of a time interval.

In most instances, the entire system bandwidth for an interval of time is not assigned to a station. But the frequency of the system is divided into sub-bands, and TDMA is used for the multiple access in each sub-band. Sub-bands are referred to as carrier frequencies and the mobile system that uses Sub-bands are known as the multi-carrier systems.

Consider this illustration, the frequency band has been shared by three users. Each user is assigned definite timeslots to send and receive data. user ‘2' sends after user ‘1’ and user ‘3’ sends thereafter. More users can be added too.

From the question, Time Division Multiple Access (TDMA) are developed to improve the efficiency and quality of digital communications and it can divide a channel into six or more time slots.

i think the answer is b.