Why did mill owners hire many women and children
a. owners wanted to keep mothers and their children together.
b. women and children would work for less money than men.
c. most men refused to do manual labor in mills.
d. women and children were more skilled and better trained

One of the main reasons why mill owners hired many women and children was because "Women and children would work for less money than men," since this was before the time of any equal pay legislation in the US. 

Sir thomas more, venerated in the catholic church as saint thomas more, was an english lawyer, social philosopher, author, statesman, and noted renaissance humanist. he was also a councillor to henry viii, and lord high chancellor of england from october 1529 to 16 may 1532. i found this information on wikipedia