Final answer:
The proper number of views necessary in a sketch for an object is typically three, known as a three-view drawing or orthogonal projection. This includes the top, front, and side views. However, up to six views can be used for complex objects.
Step-by-step explanation:
The proper number of views necessary in a sketch for an object typically ranges from one to six depending on the complexity of the object. The most common is the three-view drawing, which includes the top, front, and side views. This is also known as orthogonal projection or multiview drawing.
In some cases, more views may be necessary to fully represent the features of a complex object, but in standard technical drawing practice, three views are often sufficient. These views provide a clear depiction of the object's geometry from all angles necessary to create a complete representation. Answer choice c) six views might be considered a more comprehensive set, encompassing all primary views: front, top, bottom, right, left, and back. However, in many cases, not all six views are needed, and therefore, three views (front, top, side) are typically sufficient and considered standard.