Explanation/Reference:
DEFAULT is equivalent to RELAX_POSTAL_CODE, in which the postal code (if provided), base name, house or building number, and street type can be different from the data used for geocoding.
Incorrect Answers:
A, E: There are no match modes named RELAX_ALL or NULL.
B: Exact: All attributes of the input address must match the data used for geocoding.
C: RELAX_BASE_NAME: The base name of the street, the house or building number, and the street type can be different from the data used for geocoding. For example, if Pleasant Valley is the base name of a street in the data used for geocoding, Pleasant Vale would also match as long as there were no ambiguities or other matches in the data.
References: https://docs.oracle.com/cd/B28359_01/appdev.111/b28400/sdo_geocode_concepts.htm