what instrument did navigators use to calculate the positions of the sun and the stars?\no a caravel\no a…

Brief Explanations:

A caravel and a carrack are types of ships, not navigation - position - calculating instruments. A compass is used to determine direction, not the positions of the sun and stars. An astrolabe was used historically by navigators to measure the altitude of celestial bodies like the sun and stars for navigation purposes.

Answer:

C. an astrolabe