Final answer:
Sliced watermelon is considered a Potentially Hazardous Food (PHF) because it requires time and temperature control to prevent the growth of pathogens, hence 'a. true' is the correct answer.
Step-by-step explanation:
The question 'A cut of sliced watermelon is an example of PHF' refers to whether sliced watermelon is considered a Potentially Hazardous Food (PHF). The term PHF is used to describe foods that require time and temperature control to prevent the growth of pathogenic microorganisms and the production of toxins. Since sliced watermelon has high moisture content and is a nutrient-rich food, it supports microbial growth, making it a Potentially Hazardous Food. So, the true answer to the question is 'a. true.'