What Employment Issue Would a Labour Union Be Best Equipped

What employment issue would a labour union be best equipped to resolve?

A) Aarif is Muslim and requires working an alternate schedule during Ramadan, but other employees still have to work the standard 8:00 to 5:00 while he is observing the month for religious purposes.
B) Celia is a Latina woman who feels she did not get hired because of her ethnicity.
C) Gary has a salary that is $8,000 higher than Sarah's. Sarah and Gary are the same age with similar professional experiences. The only difference is that Sarah has a Master's degree and Gary has a Bachelor's degree.
D) Daniel is of retirement age, but wants to continue to work in his organization.
E) Sean is interested in applying for a position that requests applicants have higher credentials than what he has.