Final answer:
Blood pressure is the correct answer as it is the typical observation from a physical examination, whereas other options require blood or urine tests.
Step-by-step explanation:
The observation that is typically obtained from the physical examination of a patient is C. blood pressure. Measuring blood pressure is a common part of a physical examination because it can provide vital indicators of a person's health. Serum cholesterol level, white blood cells count in the blood, concentration of protein in the body, and amount of albumin in urine are typically measured via blood and urine tests, which are done in a clinical setting, rather than during a physical examination at the bedside.