What universal set(s) would you propose for each of the following :(i) The set of right triangles. (ii) The set of isosceles triangles.

Solution: For the first part, a set of triangles will contain both right angle triangles and isosceles triangles.
So, set of triangles will be the universal set.

For second question,
$A\cup B\cup C=\left\{1,3,5,2,4,6,0,8\right\}$
Universal set should contain $A\cup B\cup C$. Only option $C$ contains all the elements of $A\cup B\cup C$ so that is the current option.