A 7-Week-Old Infant Was Admitted After 2 Days of Vomiting

A 7-week-old infant was admitted after 2 days of vomiting. She was diagnosed of hypertrophic pyloric stenosis. The nurse at the emergency room knows that the most important nursing assessment is the:

A) amount, frequency, amd character of vomiting.
B) amount of milk and water taken at the time of last feeding
C) presence of olive shaped mass in the hypogastric area
D) amount and color of urine, skin turgor and respirations