The sampling frame for this study is a list of all known households. Option 3 is correct.
This indicates that the beginning point for the Bureau of Labor Statistics' (BLS) random sample procedure is a comprehensive list of all the households to which they have access.
So, This enables them to acquire a representative sample of the total population, guaranteeing that each family has an equal opportunity of being chosen.
Therefore, The sampling frame for this study is a list of all known households.