Answer: Hello mate!
The partition of a set is defined as a partition of the set into a nonempty subset, where the set itself is a subset of himself, then the set is a partition of himself.
a) in this we have a set of two objects; A = (1,2) the partitions of this set are: (∅), (1), (2) and (1,2). Where (∅) is the null set.
b) Now we have a set of three objects; B = (a,b,c) the partitions of this set are: (∅), (a), (b), (c), (a,b), (a,c), (b,c), (a,b,c)