2. (3 MARKS) Is the class {{x} : all atoms x} a set? Why yes or no exactiy? 3. (5 MARKS) Is the class {{x} : all sets and atoms x} a set? Why yes or no exactly? 4. (3 MARKS) Consider the solution below to this: "Prove that if A is a set then so is {A} but do NOT use an argument that involves stages explicitly". "Proof." We know (NOTEs!) that, for any sets A and B,{A,B} is a set. But {A}{A,B}, so {A} is a set by the subclass theorem. What EXACTLY is wrong with the proof above