Now moving to the second part of the map, the values, we see that map accepts values of type Integer and Long, therefore the type should cover these two types. Answers number 2,4,6 restrict the type to Integer, therefore they are excluded.
Answer 1, uses ? in declaration type, and when ever ? is used you cannot add to the collection (only adding null is allowed).
Which leaves us with answer 3 as a correct answer.