Final answer:
Calls are tracked to an advertiser's account using a unique identifier that links the call to the specific ad campaign and keywords. Call tracking services provide analytics and use dynamic number insertion to connect calls with advertisements. The correct option is C.
Step-by-step explanation:
If an advertiser uses a phone call conversion tracking feature, the calls are typically tracked to their account by a unique identifier. When a prospective customer clicks on an ad and calls the phone number provided, a unique identifier assigned to that call links it to a specific ad campaign, keywords, and the ad that triggered the call. This allows the advertiser to accurately track which ads and keywords are driving phone call conversions.
Call tracking services usually provide a pool of phone numbers that are dynamically assigned to ads. When a customer calls one of these numbers, the call tracking service associates the call with the correct campaign using the unique identifier.
Detailed analytics are then provided, including information such as call duration, caller location, and conversion data, but the unique identifier is the primary mechanism for attributing a call to a specific ad.