Full Detailed in Depth Explanation:

Oracle HCM Cloud uses a matching algorithm to identify duplicate person records during processes like hiring or candidate application, even across different legal employers within the same enterprise. This is critical to avoid creating duplicate records when a person reapplies with a changed national identifier.

Option B ("The application identifies a match if the first name, the first character of the last name, and date of birth are the same; or if the last name, the first character of the first name, and date of birth are the same") is correct. The system employs a configurable person-matching rule that typically uses a combination of key attributes—first name, last name (or initial), and date of birth—to determine if a record already exists. This rule is designed to handle cases where the national identifier changes, as it does not rely solely on that field. The "Implementing Global Human Resources" guide confirms this matching logic, noting that the system checks these attributes to prevent duplication.

Option A ("Because the national identifier has changed, the system cannot identify the matching record") is incorrect because the matching process does not depend solely on the national identifier.

Option C ("The application searches for the availability of date of birth and middle name to identify the matching record") is incorrect because middle name is not a standard required attribute in the default matching rule.

Option D ("The application cannot identify the matching record and there will be two person records available for further processing") is incorrect because the system is designed to detect matches and avoid duplicate records when possible.