The set which is the subset of every set is:
Empty set or null set.
Set--
A set is a well defined collection of the distinct objects.
The number of objects in the set is the cardinality of the set.
The set whose cardinality is zero is known as the empty set or the null set.
i.e. it is the set which is having zero element i.e. no element.
Such a set is unique.
Also, the null set or the empty set is the subset of every set.
