What’s a tenement?

A. A worker who specializes in carpentry
B. A group of poorly maintained and overcrowded apartments
C. A political official that oversees housing
D. A building designed for foreign ambassadors

B

Explanation:

"What is considered a tenement?a run-down and often overcrowded apartment house, especially in a poor section of a large city. ... any species of permanent property, as lands, houses, rents, an office, or a franchise, that may be held of another. tenements, freehold interests in things immovable considered as subjects of property"

i think it's a)sparta

porter is writing economic history because he is focusing on the cost of developing vaccines.