Which sentence uses the underlined word correctly?

a.
chris has practiced for many months and can now play his guitar good.

b.
chris has practiced for many months and can now play his guitar well.

Sign wet paint when you see this sign, what will you say to other people that is going to sit? a. you must stay away from the area because it is under construction. b. you must not sit on the bench, so just stay away from it. i’m just not sure which one is correct