**Solution:**

Given **A×B = {{p,q} , { p , r }, { m , q }, {m , r }, { } }**

or **A×B = {{p,q} , { p , r }, { m , q }, {m , r }}**

A is the set of all first elements i.e

**A = {p, m} ** ----------(Since first element contains only p and m) and

B is the set of all second elements.

**B = {q, r}** -------------(Since second element contains only q and r)