What illegal practice occurs when a property manager shows a family with a small child only properties that have playgrounds?

The practice being described is known as steering. Steering refers to the act of guiding prospective tenants or buyers towards or away from certain neighborhoods based on their protected characteristics, which can include familial status. In this scenario, by showing a family with a small child only properties that have playgrounds, the property manager is making assumptions about the family's preferences and limiting their options based on their familial status. This can not only restrict the family's choices unfairly but also perpetuate segregation and discrimination in housing.

Familial discrimination, while related, specifically addresses the unfair treatment of families with children under 18. However, steering involves the broader tactic of directing people towards certain areas and away from others, which is what is highlighted in this scenario. Redlining pertains to the practice of denying services to residents of certain areas based on racial or ethnic composition, which is not the focus here. Age discrimination would typically involve prejudices based on an individual's age, rather than their familial status. Thus, steering is the most accurate term that describes the actions of the property manager in this situation.