First, we have to add all the costs
[tex]36.45+30.11+57.43+37.32=161.31[/tex]Then, we divide this total cost by 131.69.
[tex]\frac{161.31}{131.69}=1.22[/tex]At last, we subtract the number from 1
[tex]1.22-1=0.22[/tex]This means the percentage of decrease is 22%.
Hence, none of these choices are correct.