What role did wealthy families, such as the medici, play during the renaissance?

What role did wealthy families, such as the medici, play during the renaissance?
a.
they opened public art galleries and museums where common people could see great art.
b.
they maintained armies to protect their estates where the greatest works would be safe.
c.
they travelled around europe to collect the finest works for italian artists to study.
d.
they financed great works of art and sponsored individual artists.