Concept:An electric sewing machine is powered by electricity, so the operator uses a foot pedal and keeps both hands free to guide the fabric.Explanation:Electric sewing machines do not require hand power or treadling.This allows the user to use both hands to control and guide the material being sewn.The other options are not true advantages: it cannot be used everywhere because it needs electricity, it is not inexpensive, and its top is not mainly a cutting surface.Answer:B. both hands are free to control the work.