Option D.
Here's Why:
if several customers who bought sandwiches from Asha's café complain of nausea, vomiting, and diarrhea 24 hours after eating the sandwiches, Asha should first ask the customers for general contact information. This is so that when she does open an investigation into her supplier's food quality, she will be able to contact the customers who complained and compare what happened with what she found. She will also be able to let them know about what had happened with her supplier's food quality.