Select an access control model that best prevents unauthorized access for each of the two scenarios given below. Which types of logical access controls should be used in each scenario? Justify your recommendations:
a. Top Ads is a small advertising company consisting of 12 computers that have Internet access. All employees communicate using smartphones.
b. NetSecIT is a multinational IT services company consisting of 120,000 computers that have Internet access and 45,000 servers. All employees communicate using smartphones and e-mail. Many employees work from home and travel extensively.