A complete blood count examines which components?

• A. Red blood cells
• B. Platelets
• C. White blood cells
• D. Red blood cells, platelets, and white blood cells

Answer: (D)

A complete blood count provides a broad view of blood cells by listing and measuring all three major formed elements: red blood cells, white blood cells, and platelets. It also reports related values such as hemoglobin, hematocrit, and red-cell indices, which help interpret the counts. Because it assesses all three cell types, the option that includes red blood cells, platelets, and white blood cells best reflects what a CBC examines. The other options reflect only one cell type, which would miss potential issues in the other lines and overlook the overall hematologic status.