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.

Q: Passage: The foundation of Northwestern University is traceable to a meeting on May 31, 1850 of nine prominent Chicago businessmen, Methodist leaders and attorneys who had formed the idea of establishing a university to serve what had once been known as the Northwest Territory. On January 28, 1851, the Illinois General Assembly granted a charter to the Trustees of the North-Western University, making it the first chartered university in Illinois. The school's nine founders, all of whom were Methodists (three of them ministers), knelt in prayer and worship before launching their first organizational meeting. Although they affiliated the university with the Methodist Episcopal Church, they were committed to non-sectarian admissions, believing that Northwestern should serve all people in the newly developing territory. Question: How many founders did Northwestern University have?

A: nine
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Q: Passage: In New York City in 1846, Alexander Turney Stewart established the "Marble Palace" on Broadway, between Chambers and Reade streets. He offered European retail merchandise at fixed prices on a variety of dry goods, and advertised a policy of providing "free entrance" to all potential customers. Though it was clad in white marble to look like a Renaissance palazzo, the building's cast iron construction permitted large plate glass windows that permitted major seasonal displays, especially in the Christmas shopping season. In 1862, Stewart built a new store on a full city block with eight floors and nineteen departments of dress goods and furnishing materials, carpets, glass and china, toys and sports equipment, ranged around a central glass-covered court. His innovations included buying from manufacturers for cash and in large quantities, keeping his markup small and prices low, truthful presentation of merchandise, the one-price policy (so there was no haggling), simple merchandise returns and cash refund policy, selling for cash and not credit, buyers who searched worldwide for quality merchandise, departmentalization, vertical and horizontal integration, volume sales, and free services for customers such as waiting rooms and free delivery of purchases. His innovations were quickly copied by other department stores. Question: What policy did the Marble Palace introduce? 

A: "free entrance" to all potential customers.
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Q: Passage: In international law and international relations, a protocol is generally a treaty or international agreement that supplements a previous treaty or international agreement. A protocol can amend the previous treaty, or add additional provisions. Parties to the earlier agreement are not required to adopt the protocol. Sometimes this is made clearer by calling it an "optional protocol", especially where many parties to the first agreement do not support the protocol. Question: What is a treaty that supplements a previous treaty in international law?

A:
a protocol
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