How does a person with 20/40 visual acuity compare to a person with 20/20 vision?

A person with 20/40 visual acuity does not see objects at the same distance as someone with 20/20 vision. The measurement of visual acuity is a comparison of what a person can see at 20 feet versus what a person with normal vision (20/20) can see at that same distance.

In this case, a person with 20/40 vision means that they see an object clearly at 20 feet that a person with normal vision can see clearly at 40 feet. Therefore, to see the same level of clarity as a person with 20/20 vision, the person with 20/40 vision would need to be much closer to the object. Specifically, they would need to be at half the distance, hence the explanation of needing to be twice as close to see objects clearly. This illustrates that their visual acuity is diminished compared to the standard benchmark of 20/20.

The other options do not accurately reflect the relationship between the two visual acuities as clearly as the correct choice.