The legacy program for sending files to the printer queues from the command line is:

A.
lpd

B.
lpr

C.
lpq

D.
lpp

Explanation/Reference:
From the man pages:
lpr submits files for printing. Files named on the command line are sent to the named printer (or the  default destination if no destination is specified). If no files are listed on the command-line, lpr reads the print file from the standard input.

lpq – show printer queue status
lpd – the equivalent of the printserver
lpp – there is no command lpp