Symptoms of diabetic ketoacidosis (DKA)

A 30-year-old male patient presents to the emergency department with symptoms of diabetic ketoacidosis (DKA), including severe hyperglycemia, metabolic acidosis, and ketonuria. In addition to providing immediate treatment, which diagnostic test can help differentiate between type 1 and type 2 diabetes mellitus as the underlying cause of DKA?

Urine analysis for acetoacetate

Breath analysis for acetone

Measurement of serum beta-hydroxybutyrate levels

Measurement of serum C-peptide levels