Final answer:
The best step in the Client Action Plan for qualifying for rental housing is to pay off the $1,800 judgment to demonstrate financial responsibility and improve creditworthiness.
Step-by-step explanation:
The step that should be included in a Client Action Plan to best help this client qualify for rental housing at an apartment complex is A- Pay off the $1,800 judgment. This is because outstanding judgments can significantly harm credit scores and are a red flag to potential landlords. Paying this off can demonstrate financial responsibility and significantly increase the client's attractiveness as a tenant. Additionally, once the judgment is satisfied, the client can focus on paying off the $5,000 bad debt in collections and continue to use the secured credit card responsibly to help improve her credit score over time.