The best benchmark that can be used is : The width of a license plate.
A license plate is a relatively large, flat object with a consistent width of about 12 inches. This makes it an accurate and reliable benchmark for measuring the width of the steps.
Her fingertip: Fingertip widths can vary greatly from person to person, making it an unreliable and inconsistent benchmark. Also, the width of a fingertip is usually so small relative to that of a stair.
The thickness of a dime: While dimes are all the same size, they are quite small and may not be the best choice for measuring something as large as steps.
Hence, the best benchmark is the width of a license plate.
Complete Question :
Mrs. Miller wants to estimate the width of the steps in front of her house. Select the best benchmark for her to use.
her fingertip
the thickness of a dime
the width of a license plate
how far she can walk in 20 minutes