Which GBU is associated with the small diameter bomb?

• A. GBU-31
• B. GBU-53
• C. GBU-39
• D. GBU-38

Answer: (C)

The concept being tested is identifying which bomb is the original small diameter, a lighter, narrow guided munition designed to fit more on an aircraft while maintaining precision. The small diameter bomb most commonly refers to the GBU-39, a 250-pound class bomb with a very small diameter that lets airframes carry more of them and strike targets with high accuracy using GPS/INS guidance. This is the standard small diameter bomb associated with the term.

The other options relate to related but different weapons. The GBU-53 is the Small Diameter Bomb II, a later version with a tri-mode seeker. The GBU-31 and GBU-38 are JDAMs in heavier, standard-diameter classes (around 2,000 pounds and 500 pounds, respectively) rather than the small-diameter family.