A lady walks into a store and steals a £100 quid note from the till without the owners knowledge.
She comes back 5 mins later and buys £70 of booze with the £100 note.
The owner gives her back £30 change.

How much did the owner lose?

A £30
B £70
C £100
D £130
E £170
F £200


I say £100 most say £200?