Parents of a 20-month-old infant report that he refuses food or eats poorly and that he grimaces when he swallows. he also is irritable and cries a lot. the mother is worried that he ate something inappropriate this morning, because he vomited something that looked like coffee grounds. which of the following health problems would the care team first suspect? a) rotavirus infectionb) appendicitisc) esophagitis from gastrointestinal refluxd) hirschsprung disease