Upton sinclair, lincoln steffens, and ida tarbell were

a) publishers of yellow journalism.

b) advertisers.

c) muckrakers.

d) presidential candidates.

Contributing factors  leading  to the harlem renaissance were the great migration of african americans to northern cities, which concentratedambitious  people in places where they could encourage each  other, and the first world war, which had created new industrial work opportunities for tens of thousands of people.

Aor b but i'm going with b

C) the conditions in the factory have never been questioned by the employee.

The second option is correct according to edgenuity