Final answer:
Orthographic projections in engineering involve representing an object in views from different directions, and the best choice for describing them is option b) which includes top, bottom, back, and all sides views of an object.
Step-by-step explanation:
Orthographic projections, which are used in engineering and technical drawing, involve representing an object in views from different directions. The best choice for describing orthographic projections is option b) They include top, bottom, back, and all sides views of an object. This option accurately describes how orthographic projections represent an object in multiple views to provide a comprehensive understanding of its shape and dimensions.