Certification Aid wants to implement a custom profile center using SOAP API.

To implement a custom profile center using SOAP API, the relevant SOAP API methods are:

Describe (B) - This method is used to retrieve metadata about objects, such as their fields and properties. It is useful for understanding the structure of the data you are working with.

Update (C) - This method is used to update existing records in Marketing Cloud. It is essential for modifying subscriber data in the custom profile center.