Answer:
The correct answer is B) The introductory sentence cannot be alone.
Step-by-step explanation:
The colon after "including" should be removed because while it introduces a list of items and places the speaker needs to stop at, the introductory sentence cannot be alone. The introductory sentence "I need to stop at several places, including" would be grammatically incorrect. The situation could be solved by either removing the colon, which would be the most obvious answer, or removing "including".
Also, "including" already introduces the idea of a list so the colon would be redundant.