Denise is constructing a square in which two of its vertices are points m and n. she has already used her straightedge and compass to construct the lines and arcs shown. what should denise do for her next step? a) use a straightedge to draw a horizontal line that contains point o. b) use a straightedge to draw mo. c) place the point of the compass on point m and draw any arc above it. d) place the point of the compass on point n and draw an arc that intersects n o, using mn as the width for the opening of the compass.