Which of these business rule(s) can be found to be correctly represented in the class diagram?

Make Me A Star Productions runs an annual talent competition for aspiring amateur singers.

Four business rules have been identified:

1) A contestant is allowed to sing 1 or 2 songs in a performance.

2) An audition may be attended by up to 50 contestants.

3) A contestant is always given an audition.

4) A song can only be used in one performance.

Which of these business rule(s) can be found to be correctly represented in the class diagram?
A . 1 only
B . 1 and 2
C . 2, 3 and 4
D . 3 and 4