Symbols and their units (And what is X ?)

Hello people ! Once again I need your brain-nourrishing feedback to understand something !

I cannot find on google what the X symbol means. Google will sort any multiplication sign there is in an equation even if I'd write "symbol X electronic SI". I think it'll be faster if I ask here, and also because I have an exam coming up and we haven't seen anything about X and the units of Z, and stuff.

So I'll simply post a screen capture of my pre-exam online test, you will see my 2 errors:

**broken link removed**

Reactance
reactance symbol - Google Search

So both Z and X have the unit omega ?

My multiple choice answer was weird because it had W twice, and omega only once... I guess it was a trap.

edit: thank you by the way !

Z is impedance and X is reactance. The former is complex and is made up of the reactance (imaginary) and resistance (real) - all of which have units of ohms.