The shop keeper lost:
G) Other (1000rs)
The lady pays with 1000 rs, the shopkeeper then excanges the note for a 800 and 200 note, he keeps the 200 note and gives the 800 + the product to the lady.
At this point the shop keeper made no loss. Then the shop owner of shop b comes and tells him the 1000 note was fake, he takes his 1000rs back. The shop keeper now has -800rs left. The diffrence between -800rs and 200rs is 1000rs.
poor guy