Error in Set Tutorial

Question

One of these statements are incorrect. These statements are CONTRADICTORY.

"NO REPETITIONS are allowed"
"The size property returns the number of DISTINCT values"

Answer 1

They are not contradictory

Answer 2

They are not.

Answer 3

not contradictory: the first statement imply the second statement... If "no repetitions are allowed", then the size is necessarly the number of "distinct" values. That's implicit, but in teaching context that's important to not rely on implicit and rather be explicit, even if that provides redundant information ^^