Custom affinity audiences are defined as:

• A. Niche user groups that deliver substantive reach
• B. Broad demographic groups based on age
• C. Audiences determined by search history alone
• D. Unique audiences created from keywords, URLs, inputs from apps, and map locations

Answer: (D)

Custom affinity audiences are built by defining a unique group through signals that reflect what people care about and how they behave online. You create them using keywords that describe topics and interests, URLs of sites they visit, inputs from apps they use, and map locations they frequent. By combining these signals, Google identifies users who show similar interests and intents, giving you a more targeted reach than broad demographics or a single data source like search history. This is exactly about forming a distinct audience from multiple signals—keywords, URLs, app inputs, and map locations.