Which one of the following is not a valid memory unit?

مندرجہ ذیل میں سے کون سا ایک درست میموری یونٹ نہیں ہے؟

None of these

XB is not a valid memory unit.

As standard memory units include KB (Kilobyte), MB (Megabyte), GB (Gigabyte), and so on.

Memory units follow binary prefixes and progressions.

But XB does not exist in this system.