Q1: What is the name of the printer which prints all the A's in a line before all the B's?

ANS:C - Line printer

Line Printer is not the correct answer. You have copied this question from CoolInterview site but Definition of line printer from wikipedia is below,

"The line printer is an impact printer in which one line of text is printed at a time. They are mostly associated with unit record equipment and the early days of digital computing, but the technology is still in use. Print speeds of 600 lines-per-minute (approximately 10 pages per minute) were achieved in the 1950s, later increasing to as much as 1200 lpm. Line printers print a complete line at a time and have speeds in the range of 150 to 2500 lines per minute. The different types of line printers are drum printers and chain printers".