Which of the following is correct?

Q. Which of the following is correct?

1. All members of photolithotrophic autotrophs are also members of algae, but not all members of algae are members of photolithotrophic autotrophs
2. All members of algae are also members of photolithotrophic autotrophs, but not all members of photolithotrophic autotrophs are members of algae
3. All members of photolithotrophic autotrophs are members of algae, and all members of algae are members of photolithotrophic autotrophs
4. No member of photolithotrophic autotrophs is a member of algae

Answer: All members of algae are also members of photolithotrophic autotrophs, but not all members of photolithotrophic autotrophs are members of algae