Which of the Following Is the Best Interpretation of the Graph

Which of the following is the best interpretation of the graph below of mussel size (x-axis) versus energy gain (line graph, left y-axis) , and number of mussels eaten per day (histogram, right y-axis) ?

A) Mussels are selected as food sources by crabs.
B) Crabs select mussels in a way that maximizes their energy gain.
C) Mussel size does not seem to be a good predictor as to which mussel hungry crabs will select.
D) Crabs tend to consume most of the largest mussels.