Farm B would be the answer.
To find the decimal value of all the farms, you should divide 11/20 equaling 0.55 purple flowers, for Farm A. To find the decimal value of Farm C it would just be 0.40.
Now if you compare all of the decimals of blue flowers, you can see that Farm B has the most amount of blue flowers, with 0.60.
Therefore the answer is Farm B.
Hope this helped.