Why does a customer need a keyboard with an HP ap5000 AiO POS System?

A.
to enter input data such as purchasers’ sales items and credit card data

B.
to use the integrated software to calibrate the resistive touchscreen

C.
to unbundle the operating system during initial system setup

D.
to act as a backup data input mechanism if the touchscreen fails

Explanation:

Reference:
ftp://ftp.moteselectronics.com/HP/All%20In%20One%20PC/AP5000%20(POS%20System)/hp%20ap
5000.pdf (page 22, see 4th row of the table)