Step 1: Understanding the Concept:
This question tests dangling modifiers. An introductory modifying phrase must logically and grammatically modify the subject of the main clause that immediately follows it.
Step 2: Detailed Explanation:
The introductory phrase is "Despite seeming tame and intelligent." This phrase is intended to describe the Gorilla. However, the subject of the main clause is "the state troopers." The current sentence structure illogically suggests that the state troopers seemed tame and intelligent. This is a dangling modifier.
To correct this error, we can change the introductory phrase into a full clause with its own subject.
Option (D) does this by creating the subordinate clause "Although it seemed tame and intelligent." The subject "it" clearly refers to the Gorilla, and the modifier is no longer dangling. The rest of the sentence can then follow correctly.
Options (A), (B), (C), and (E) are all phrases that would continue to incorrectly modify "the state troopers."
Step 3: Final Answer:
The original introductory phrase dangles because it modifies "the state troopers" instead of the "Gorilla." Converting the phrase to a clause with its own subject ("it") resolves the error.