Language of Sets---Discrete Math

Question

Which of the following sets are equal? (Select all that apply.)

A = {3, 4, 5}

B = {x  R| 2 ≤ x < 6}

C = {x  R| 2 < x < 6}

D = {x  Z| 2 < x < 6}

E = {x  Z+| 2 < x < 6}

I selected A, C, D, and E, but it says it is incorrect. If you could explain how you get your answer, that would be very helpful!

Answer 1

C is wrong because the reals are continuous. So for instance, 4.573 is in C, but it's not in A, D, or E. Take C out of your answer, and you're good.