Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

Example input: Passage: Martin Luther married Katharina von Bora, one of 12 nuns he had helped escape from the Nimbschen Cistercian convent in April 1523, when he arranged for them to be smuggled out in herring barrels. Suddenly, and while I was occupied with far different thoughts, he wrote to Wenceslaus Link, “the Lord has plunged me into marriage. At the time of their marriage, Katharina was 26 years old and Luther was 41 years old. Question: In a letter who did Luther credit for his union with Katharina?
Example output: the Lord
Example explanation: The paragraph clearly states that, Luther has credited the Lord for his union with Katharina, hence the Lord is correct answer.
Q: Passage: The University is organized into eleven separate academic units—ten faculties and the Radcliffe Institute for Advanced Study—with campuses throughout the Boston metropolitan area: its 209-acre (85 ha) main campus is centered on Harvard Yard in Cambridge, approximately 3 miles (5 km) northwest of Boston; the business school and athletics facilities, including Harvard Stadium, are located across the Charles River in the Allston neighborhood of Boston and the medical, dental, and public health schools are in the Longwood Medical Area. Harvard's $37.6 billion financial endowment is the largest of any academic institution. Question: What river is located in the vicinity of the school?
A:
Charles