Question: Medco Health Solutions, Inc. was an American Pharmacy Benefits Management (PBM) company which served more than 65 million people, before it was ultimately acquired by Express Scripts, in April of which year?
Sentence (from "Express Scripts"): As of 2017, the company is the 22nd-largest in the United States as well as the largest pharmacy benefit management (PBM) organization in the United States.
Relevant evidence: No