Point 10 — “Which” — Essential or Non-Essential?

What do we see?

Which appears in the options or immediately after the blank.

What do we understand?

Ask: does the sentence retain its meaning if the which clause is removed?

If yes → make the which clause non-essential (set it off).
If no → make it essential (no separating punctuation).

Question 1 of 4

As a behavioral ecologist, Dr. Yuki Matsumoto of Hokkaido University recognizes that animals sometimes make irrational foraging decisions. Matsumoto’s research can thus address anomalies that classical evolutionary ______ assume that organisms always maximize reproductive success — cannot explain.

Which choice completes the text so that it conforms to the conventions of Standard English?