To answer this question, we need to examine each part of the sentence to identify any errors.
Option A) a - This part of the sentence does not contain any error. It is grammatically correct.
Option B) b - This part of the sentence contains an error. The word "visit" should be followed by the preposition "to" when referring to a location. Therefore, the correct phrase should be "want to visit" instead of "want to visit."
Option C) c - This part of the sentence does not contain any error. It is grammatically correct.
Option D) d - This part of the sentence does not contain any error. It is grammatically correct.
The correct answer is Option B. This option is incorrect because it contains an error. The corrected phrase should be "want to visit" instead of "want to visit."