In which housing situation would you be legally allowed to deny children?

The correct choice reflects the legal allowance for housing designed specifically for older adults. The Fair Housing Act includes provisions that permit certain housing developments to limit residency based on age, particularly those that are designed to serve older individuals, typically aged 62 and older. These properties are often referred to as "senior housing" or "age-restricted housing."

In this context, a property may legally refuse to rent to families with children if it adheres to the guidelines of being an age-restricted community. This serves the purpose of providing a living environment better suited to the needs of older adults, which can include considerations for peace, safety, and social engagements that are appropriate for seniors.

When examining the other options, the absence of a playground, a strict quiet hour policy, or the presence of children already living at the property do not constitute legal grounds for discrimination against families with children. The law protects familial status, meaning that housing cannot deny access to families simply based on the presence of children unless it meets specific age-restriction criteria as stated.