Final answer:
The pharmacy technician would utilize the online Purple Book to check for interchangeable biological drugs, as outlined by the FDA.
Step-by-step explanation:
A pharmacy technician would use the online Purple Book to determine if a drug has been identified as an interchangeable biological drug. The correct answer to the question is option A: the Purple Book. This book, maintained by the U.S. Food and Drug Administration (FDA), provides a list of approved biological products, including any biosimilar and interchangeable products. Understanding the therapeutic equivalence of generic drugs is crucial, and resources such as the online Purple Book aid in ensuring that the medicines provided meet the necessary standards for efficacy and safety.