Blockbusting could be described as...

Blockbusting is a practice that involves subtly influencing homeowners to sell their properties, often by using tactics that instill fear or anxiety about changing community demographics. Real estate agents or investors might create a sense of urgency or panic by suggesting that certain groups are moving into the neighborhood, which could lead to a decrease in property values—prompting homeowners to sell quickly, sometimes at lower prices. This practice not only disrupts communities but is also considered unethical and is illegal in many jurisdictions, as it can exploit people's fears and contribute to racial segregation.

The other choices do not encapsulate the nature of blockbusting effectively. Educating homeowners on market trends can be seen as a legitimate real estate practice; guiding buyers towards more expensive homes doesn't connect to the coercive nature of blockbusting; and providing free property assessments is a standard service that does not involve the manipulation associated with influencing homeowners to sell out of fear. Hence, the identified answer accurately reflects the deceptive and coercive characteristics of blockbusting.