which of the following groups is an example of a well-defined set?
a. students with long hair
b. women with fair complexion
c. professionals who are short and with long pants
d. local female singers whose name starts with vowel

2.which of the following sets is equal to{a, e,i,o,u}?
a.{1, 2,3,4,5}
b. {b, c, d, e, f}
c. {a, e, I, o, u}
d. {a, e, i, o}

3.which of the following is an example of an empty set?
a. set of odd numbers which are multiples of 5
b. {xl x is a yellow flower}
c. {xl x is a country in Asia which has Euro as its currency }
d. set of mammals​