2. If U = {a, b, c, d, e, f). Which of the following is not a subset of the universal set?
a. {a,b,c}
b. {g, e, f}
d. { a, b, c, d, e, f}
c. { c, d, e}
3. Which of the following sets is empty?
a. Set of counting numbers between 8 and 9.
b. Set of composite numbers between 7 and 19.
c. Set of even numbers divisible by 2.
d. Set of prime numbers between 5 and 10. 993​