At 1337 ZT on July 17, in DR position LAT 30° 56.8' S, LONG 039° 36.5' W, you observe an amplitude of the Moon. The upper limb of the moon is on the visible horizon, bearing 263.0°psc. The variation is 20°W. What is the deviation?

Correct Answer: Option B — 3.6°E

Moon amplitude observations require correcting for upper or center limb positions and semi-diameter. Using latitude and declination, solve for true amplitude, apply variation for magnetic, and find deviation against the observed psc bearing.