What is the strongest factor influencing migration selectivity?
a. age
b. education level
c. gender
d. relation
e. race

I would go with the answer E). Just because slavery ended years ago doesn't mean that's its still over even to this day, it use to be about gender as well back than where women couldn't vote but no one cares about that today, the things people care about is race because as the famous quote someone said, humans hate what they don't understand, so most races don't understand why people are all different, so they want to hate them since they don't understand and also get higher authority as well, but to get back to topic race is the most common thing today that encourages people to leave and migrate cause they might not feel welcome.

The answer is choice b