Final answer:
Perform a combination of secondary research and interviews to search for answers to customer claims.
Step-by-step explanation:
When searching for answers to customer claims, you should perform a combination of secondary research and interviews. Secondary research involves gathering information from customers and other stakeholders, as well as finding expert information through books or other sources. Interviews allow you to directly ask the customer about their claim and do a root cause analysis to identify the real problem. By combining these two types of research, you can gather comprehensive information to address customer claims effectively.