Which best practice is advisable when optimizing ad groups within a placement–targeted display campaign?

Which best practice is advisable when optimizing ad groups within a placement–targeted display campaign?

·          For each ad group, target groups of placements with similar themes

·          Create a separate ad group for each placement

·          Target a broad collection of placements with a single ad group

·          Move automatic and managed placements into separate ad groups

Correct Answer is :

For each ad group, target groups of placements with similar themes

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