Final answer:
b) because
The sentence is correctly completed by using 'because', which indicates the reason why handling produce is critical, linking it to the consequences on its appeal and nutrient value.
Step-by-step explanation:
The correct word to complete the sentence is 'because'. Therefore, the complete sentence should read: 'Handling produce is critical because bruised, wilted, or overripe produce loses both appeal and nutrient value.' This word provides a cause-and-effect relationship between the handling of produce and the consequence it has on the appeal and nutrient value of the produce.