Which best describes why the italian renaissance spread to northern european cities?

a.)cultural conditions that the renaissance grow in italy during the early 1400s began to appear in northern european cities during the mid-1400s.
b.)religious support that the renaissance grow in italy during the early 1400s began to expand in northern european cities during the mid-1400s.
c.)government support that the renaissance grow in italy during the early 1400s began to expand in northern european cities during the mid-1400s.
d.)population growth that the renaissance grow in italy during the early 1400s began to appear in northern european cities during the mid-1400s.