In Advanced Encryption Standard $($AES$),$ the s$-$boxes are public. So how does that help security?

Question $11$ options:

s$-$boxes enhance security by doing block level substitutions thereby improving the compression

s$-$boxes enhance security by doing block level substitutions thereby improving the diffusion

s$-$boxes enhance security by doing byte level substitutions thereby improving the compression

s$-$boxes enhance security by doing byte level substitutions thereby improving the diffusion