At 1523 ZT on 14 June, in DR position LAT 31°58'S, LONG 48°42'W you observe an amplitude of the Moon. The center of the Moon is on the visible horizon and bears 118.0°psc. The variation is 10°W. What is the deviation?

Correct Answer: Option B — 2.1°W

Moon amplitude observations require calculating the body's declination adjusted for the observer's position and local time. By converting the true computed bearing through application of variation and standard compass readings, the resulting deviation is determined to be 2.1°W.