Troubleshooting garbled printouts

A customer has called you with a printer problem where the printouts are completely garbled. Instead of a text document from a word processor, the page is filled with random characters, lines, and block graphics. What’s the best next step to help troubleshoot the problem?

A) Replace the toner or ink in the printer

B) Reboot the computer

C) Use the printer’s built-in diagnostics to print a test page

D) Use different weights of paper