Which of the following scale is a reducing scale

There is a wide variation in sizes for engineering objects. Some are very large (e.g. Aeroplanes, rockets, etc) Some are very small (wristwatch, MEMs components)

There is a need to reduce or enlarge while drawing the objects on paper. Some objects can be drawn to their actual size. The proportion by which the drawing of an object is enlarged or reduced is called the scale of the drawing.

A scale is defined as the ratio of the linear dimensions of the object as represented in a drawing to the actual dimensions of the same. Drawings drawn in the same size as the objects are called full sized drawing.

Representation Factor (R. F)

\({\rm{R}}.{\rm{F}} = \frac{{{\rm{Length}}\:{\rm{of}}\:{\rm{an}}\:{\rm{object}}\:{\rm{on}}\:{\rm{the}}\:{\rm{drawing}}}}{{{\rm{Actual}}\:{\rm{length}}\:{\rm{of}}\:{\rm{the}}\:{\rm{object}}}}\)

Reducing scale: 1:3

Enlarging scale 3:1, 3:2

Full-Size Scale 1 ∶ 1