Cancer

Step 1: Understanding carcinoma.
Carcinoma refers to cancer that originates in epithelial cells, which line the body's organs and structures.
This is the most common type of cancer.
Step 2: Review of other options.
Leukemia: This is a type of cancer that affects blood cells, not epithelial cells.
Sarcoma: This cancer affects connective tissues, such as bones, muscles, and cartilage.
Emphysema: This is a lung condition, not a form of cancer.
Thus, the correct answer is (D) Carcinoma.