Answer:
B. From another country
Step-by-step explanation:
The word exotic, as used in the sentence above illustrated that the plants were foreign; they were introduced from another country and they are not native to the United States.
Literally, the word "exotic" is used to describe things of foreign origin. With the way it was used in the sentence, it shows that the kudzu (the object it describes) is not planted in the United States.
In fact this claim was supported at the second part where the sentence reads "Travelers brought them to the United States.....";
So, it's safe to make the above claim that exotic as used here means from another country.