What is the equation for calculating magnification?

The correct choice for calculating magnification is determined by the relationship between the image size and the actual size of an object. Magnification is specifically defined as the size of the image you're observing divided by the actual size of the object being viewed.

This relationship allows you to understand how much larger an image appears compared to the object itself. For example, if an object's actual size is 2 cm and the image size is 8 cm, the magnification would be 8 cm (image size) divided by 2 cm (actual size), resulting in a magnification factor of 4. This means the image appears four times larger than the actual object.

The other options do not represent this relationship correctly. Adding the image size and actual size does not give a meaningful measure of magnification because magnification relies on the ratio of these two sizes rather than their sum.