At 1547 ZT on 22 May, in DR position LAT 45° 12.8' N, LONG 028° 15.4' W, the Moon's upper limb is observed on the visible horizon, bearing 120.0° psc. Variation is 2° W. What is the deviation?

Correct Answer: Option C — 2.6°E

Determining compass deviation requires finding true bearing from celestial calculations, applying variation to find magnetic bearing, and comparing it to the standard compass reading (True = Magnetic + Variation; Magnetic = Compass + Deviation).