Question

what is used to divide floor plans into sections?
gridlines
section cuts
cutting plane lines
details

Explanation:

In architectural drawings, cutting plane lines are used to indicate where a section cut is made. Section cuts are the actual cuts through the building, but the lines that define where those cuts occur (cutting plane lines) are what divide the floor plan into sections for the purpose of showing internal details. Gridlines are for layout and alignment, and details are specific parts of the drawing.

Answer:

cutting plane lines