Consider the sentence below.

"Only after the second interview did the researchers realize how strongly the wording had influenced the responses."

The sentence combines marked word order with different tense and clause relationships.

Analyze the statements below.

I.The initial restrictive adverbial expression is associated with subject-auxiliary inversion in the main clause.
II.The auxiliary "did" carries past-tense marking, while "realize" remains in its base form.
III.The past perfect in "had influenced" places the influence after the researchers' realization.
IV.The clause introduced by "how strongly" functions as a complement of "realize."

It is CORRECT what is stated in: