how are gram positive and gram negative cell walls different?

Question:how are gram positive and gram negative cell walls different?

1. gram-negative cells have a single layer of peptidoglycan and an outer membrane and gram-positive cells have a thick layer with teichoic acids

2. gram-positive cells have a single layer of peptidoglycan and a periplasmic space while gram-negative cells have a thick layer with teichoic acid

3.gram-negative cell walls have a thick layer of peptidoglycan and gram-positive cells have no peptidoglycan but have teichoic and mycolic acids

4.None of the above

Answer:1