I can't explain it but
It's definately not a case where both answers are correct. Max lift to drag ratio is the exact answer since it's like this max CL/CD ratio.
The other two with CD/CL max, CD/CL min are incorrect.
If there's a minimum ratio between the two then it's not the one.
If it's max ratio then it still has to have CL before CD
MAX CD/CL ratio and MAX CL/CD ratio are two different things.
I can't explain it on perf level but my teacher gave us a similiar answer option and I didn't like it one bit.