To solve this question, the user needs to know the meaning of the given words and the context of the sentence. The user needs to determine which word best fits in the blank space to make the sentence grammatically and semantically correct.

The correct option is:

C. indigenous

Explanation:

The word "indigenous" means native or originating from a particular place. In the given sentence, the speaker is stating that they have never seen these flowers before in New England, which implies that the flowers are not native to New England. Therefore, the correct word to fill in the blank is "indigenous."

Option A, "ingenuous," means innocent, naive, or candid. This word is not appropriate in the given sentence because it does not refer to the flowers' origin.

Option B, "fluent," means able to express oneself easily and articulately. This word is not appropriate in the given sentence because it does not refer to the flowers' origin.

Option D, "exigent," means pressing, urgent, or requiring immediate attention. This word is not appropriate in the given sentence because it does not refer to the flowers' origin.

Therefore, the correct answer is:

The Answer is: C. indigenous