The phrase "กินปูนร้อนท้อง" is a Thai idiom that means "to feel angry or upset." Among the given options, only option ค (คนทำผิดมักจะแสดงอาการพิรุธออกมา) directly relates to the idiom, as it suggests that people who make mistakes often show signs of anger or frustration. Therefore, this option is the most fitting explanation for the idiom "กินปูนร้อนท้อง."