What two symbols are safe to use in Microsoft Excel file names?

What is the full meaning of rfid in computer

Linux is distributed under gnu gpl. why is this important? a. it ensures that only torvalds can profit from the sale of linux b. it prevents unknowledgeable users from downloading programs they don't know how to operate. c. it provides protection for the developers who created linux. d. it states that anyone can copy, modify, and share the program if changes are made public.

Octothorpe is another name for what common computer keyboard symbol?