The correct answer is A. 1.10 to 1.20.
The shape factor is a dimensionless number that is used to determine the effective area of a beam section. It is defined as the ratio of the area of the cross-section to the product of the depth and the width of the section.
The shape factor of a standard rolled beam section varies from 1.10 to 1.20. This means that the effective area of a standard rolled beam section is between 110% and 120% of the area of the cross-section.
The shape factor is important because it affects the strength of the beam. A beam with a higher shape factor is stronger than a beam with a lower shape factor.
The shape factor is also important because it affects the deflection of the beam. A beam with a higher shape factor will deflect less than a beam with a lower shape factor.
The shape factor is a useful tool for engineers who design beams. It allows them to select the most efficient beam section for a given application.
The other options are incorrect because they do not represent the range of shape factors for standard rolled beam sections.