What is a name given to the process of a CPU switching between applications very quickly?

For what is the Atanasoft–Berry Computer best known?

a. It was the first computer to use vacuum tubes instead of mechanical switches. b. It was the first computer to use the binary system. c. It was the first computer to incorporate a magnetic tape system. d. It was the first computer used as a mechanical calculator.

For security reasons, you should _________________________ of your Microsoft account when you are finished using a public or shared computer.

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