Which of the following is incorrect?

A. For a set to be subset to any set it should have less than or same number of elements. If a set contains finite no. of elements its subset also gets number finite in the set.

So, this is true.

B. The set is defined by P = {x : x – 8 = − 8}

X -8 = -8

X = 0

∴ P = {0}

This is a singleton set.

This Is also true.

D. It is a rule that non-empty set has 2 subsets they are

They are subset to itself and null set is the subset to that non-empty set.

So, it is also true.

C. It is a property that null set is proper set to every other set except to itself. This means Some sets only has proper subset.

So, it is false.

∴ option(C) is correct answer.