To express "5 is to 1 as 20 is to 4" in fractional notation, the correct response would be:
5/1 = 20/4
So, if we were to select from your provided options, the correct proportional notation should resemble:
5/1 = 20/4
However, since that specific choice doesn't seem to be listed, it's important to clarify:
The equality should accurately represent the relationships, so the correct notation could also be indicated in the ratio format as:
5:1 :: 20:4
This communicates the same meaning directly as a ratio. Please ensure all options are accurately utilized if necessary.