Final answer:
The conversion factor to convert the recipe to serve 20 people instead of 8 is 2.5.
Step-by-step explanation:
To convert the recipe to serve 20 people instead of 8, we need to find the conversion factor. The conversion factor is the ratio of the new quantity to the original quantity. In this case, we want to find the ratio of 20 to 8.
Conversion factor = New quantity / Original quantity
Conversion factor = 20 / 8 = 2.5
Therefore, the correct answer is A) 2.5.