A horizontal distance measurement by a total station is amea

A horizontal distance measurement by a total station is
a-measured from the round at the total station to the ground at the prism
b-derived from a total station measuring slope distance and horizontal angle
c-requires height of instrument and height of target to reduce to horizontal
d-requires measurement of zenith angle for use in plane coordinate calculations

Solution

the horizontal distance measured by total station is

a) measured from the round at the total station to the ground at the prism.

using total station. infrared radiation is sent from the total station to the prism and the ray is reflected back. so diatace is calculated by the total station directly.