If the Sun's observed altitude is 27°12', the zenith distance is __________.

Correct Answer: Option A — 62°48'

Zenith distance (z) is the angular distance from the observer's zenith to a celestial body, calculated as 90 degrees minus the observed altitude (Ho). Subtracting 27°12' from 89°60' yields 62°48', representing the exact arc length along the vertical circle.