The correct answer is A and C. The original tools used by the Greeks to build a true geometric construction are either the compass or the straightedge. A compass is a V-shaped tool used to make circles or arcs. One side of the V has a pencil and the other one has a tip. Once the user decides the size of the circle, the compass is turned around. A straightedge is a tool used for making straight lines. A ruler might be used as a straightedge by ignoring the measuring lines on it.
