Teacher:This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
Teacher: Now, understand the problem? Solve this instance: Passage: One of the best known sporting events in the city is the Boston Marathon, the 26.2-mile (42.2 km) race which is the world's oldest annual marathon, run on Patriots' Day in April. On April 15, 2013, two explosions killed three people and injured hundreds at the marathon. Another major annual event is the Head of the Charles Regatta, held in October. Question: When is the head of Charles Regatta held?
Student:
October