You observe the lower limb of the Sun at a sextant altitude (hs) of 46°20.3' on 1 April. The index error is 4.5' off the arc. The height of eye is 57 feet (17.4 meters). What is the observed altitude (Ho)?

Correct Answer: Option D — 46°32.6'

Apply index error (off the arc is additive) to hs to find sextant altitude. Correct for dip (57 ft) and altitude correction (Sun lower limb) using the Nautical Almanac tables. The sum of these corrections to the corrected hs yields the Ho of 46°32.6', following standard Bowditch celestial reduction procedures.