1 and (1) are wrong. Any set has at least one subset, and this subset is itself, and an empty set is no exception, so it cannot be said that an empty set has no subset. (

(2) No, it should be said that an empty set is a proper subset of any non-empty set (or an empty set is a subset of any set). For example, the set A={ 1, 2,3} has eight subsets, and there are other subsets besides the empty set. The empty set is his proper subset. For example, the empty set itself has a set, which means that he has a set besides himself.

(3) Yes, an empty set is a set without any elements.

(4) No, there is only one subset of the empty set, which is the empty set itself.

2.b is included in A and C, with parallelogram having the widest range (which can also be understood as requiring the least graphics) and square requiring the most.