2. It is the overall set of all the elements under discussion. B. Elements B. null set C. subset D. universal set 3. List all the elements in A = {vowels in the word "Mathematics") B. {a,e,a,i} B.{a,e,i) C. {e,i) D.) 4. Which of the following is a well-defined set? E. {a happy child) F {a popular actress) G. fa favorite book by my classmate) H. {a grade 7 Mathematics book in the library)