A 16 year old male with a day history of malaise, weakness and vomiting. He was diagnosed with Insulin dependent diabetes mellitus 3 years prviously. Which ONE of the following supports a diagnosis of diabetic ketoacidosis: 1) Abdominal pain at onset 2) A serum bicarbonate of 10 mmol/l 3) A serum glucose 14 mmol/l 4) Decreased appetite in the past few days 5) Shallow respirations