What kind of zoning would require that a developer build 10% of the homes in a subdivision for low-income families?

Inclusionary zoning is the correct choice for this question because it specifically refers to policies intended to promote the creation of affordable housing within new developments. This type of zoning mandates that a percentage of the new housing units — in this case, 10% — be set aside for low-income families or individuals. The goal of inclusionary zoning is to ensure that economically diverse communities are developed, rather than allowing for strictly market-rate developments that might contribute to social and economic segregation.

In contrast to this, conditional zoning allows for certain uses of property under specified conditions, which may not specifically address the inclusion of affordable housing. Exclusive zoning is focused on designating certain areas for particular types of developments, often to maintain certain community standards or exclusivity, and does not involve mandates for affordable housing. Comprehensive zoning involves a broad plan that outlines land use regulations for an entire area, but it does not inherently include stipulations about low-income housing requirements.

Thus, inclusionary zoning stands out as the mechanism specifically designed to integrate affordable housing within the overall development plan, making it the clear answer to the question.