Final answer:
The correct answer is (a) Product name, hazard pictograms, signal words, and hazard statements, as these are the key elements required under WHMIS 2015 for a supplier label.
Step-by-step explanation:
Under WHMIS 2015, a supplier label must include the following key elements: the product name, hazard pictograms, signal words, and hazard statements. Therefore, the correct answer to the student's question is option (a) Product name, hazard pictograms, signal words, and hazard statements. The supplier labels are a crucial aspect of product safety and are designed to provide necessary information to safely handle and work with hazardous materials, by offering details about the chemical's identity and the specific hazards it may pose.