For Shared Preferences methods, what does the method return to  the application if the preference is undefined?

A _________ firewall applies a set of rules to each incoming and outgoing IP packet and then forwards or discards the packet.

Fill in the blank(s) with the appropriate word(s).

Case-Based Critical Thinking Questions ? Case 1: BrainPower Tutoring ? The owner of BrainPower Tutoring needs an application that clients can use to request an appointment. The application should allow users to enter their name, subject, preferred appointment time, and phone number, and submit their request. It should also allow them to print their appointment request, clear the screen, and exit the application. The tutoring center has some clients with visual impairments, so the application should be easy for them to use. Which of the following controls should receive access keys?

A. name B. subject C. phone number D. all of the above