Are these sentences correct and which one is better? Thanks a lot!
<A>Starting from 2015, the children of migrant workers who have residence permit for longer than 6 months will be allowed to take the national college entrance exam in Beijing。
Starting from 2015, the children of migrant workers holding residence permits for longer than 6 months will be allowed to take the national college entrance exam in Beijing。
I am not sure about the plural forms such as "permit" vs. "permits", "(with or without 'for') longer than 6 months" etc.
Thanks a lot.