A map projection in which its reference ellipsoid is Clarke 1866 with origin latitude at the equator and origin longitude at the central meridian.

• A. Universal Transverse Mercator
• B. Mercator Projection
• C. Lambert Conformal Conic
• D. Azimuthal Equidistant

Answer: (A)

This tests how the ellipsoid and the origin settings define a projection’s framework. Clarke 1866 is the NAD27 ellipsoid, a historical model used with many older UTM datasets. When the latitude of origin is set at the equator and the longitude of origin is the central meridian, you’re describing a transverse Mercator scheme that is applied zone by zone. The Universal Transverse Mercator system uses exactly this setup: a transverse Mercator projection in each 6-degree-wide zone, with the equator as the latitude origin and the zone’s central meridian as the longitude origin (along with its characteristic false easting and scale factor). The other projections rely on different geometry—Mercator is a global cylindrical form with a single central meridian, Lambert Conformal Conic is a conic with standard parallels, and Azimuthal Equidistant centers on a single point—so they don’t match the described parameter combination.