The correct answer is B. Purchasing ingredients from unsafe sources, holding foods at the wrong temperatures, poor hygiene practices, using contaminated tools & equipment, improper cooking of foods.

Reference:

Purchasing ingredients from unsafe sources, holding foods at the wrong temperatures, poor hygiene practices, using contaminated tools & equipment, improper cooking of foods are the 5 most common risk factors that compromise food safety. Implementing proper food handling procedures includes ordering from reputable and safe suppliers, as well as training staff on food safety standards.

Reference:

https://extension.psu.edu/5-most-common-risk-factors-for-a-foodborne-illness-outbreak