Fact 1: Viruses are so small that they can be seen only with an electron microscope.

Fact 2: On the surface of each microscopic color filter is also a microscopic lens.

Given the two facts above, answer the question "Viruses are so small that to see them a scientist would have to use what kind of lens?" with the following options: 
- Refract it
 - refraction of light
 - an electron lens
 - an image
 - rays or beams
 - bending light rays
 - A computer
 - flashlights


 

   an electron lens      