Final answer:
The Seaman to Admiral (STA-21) program is a Commissioning Program for Enlisted Personnel in the United States Navy.
Step-by-step explanation:
The Seaman to Admiral (STA-21) program is best described as a Commissioning Program for Enlisted Personnel. This program is designed for enlisted personnel in the United States Navy and provides an opportunity for them to earn a commission and become officers. Through the program, qualified individuals can receive a college education and be commissioned as naval officers.