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.

Example Input: Passage: To qualify for participation in the auctions, banks must be able to offer proof of appropriate collateral in the form of loans to other entities. These can be the public debt of member states, but a fairly wide range of private banking securities are also accepted. The fairly stringent membership requirements for the European Union, especially with regard to sovereign debt as a percentage of each member state's gross domestic product, are designed to insure that assets offered to the bank as collateral are, at least in theory, all equally good, and all equally protected from the risk of inflation. Question: What must be a part of a states Gross Domestic Product in order for them to be considered for particpation in auctions?
Example Output: sovereign debt

Example Input: Passage: While Brazil was fighting the US through the WTO's Dispute Settlement Mechanism against a heavily subsidized cotton industry, a group of four least-developed African countries – Benin, Burkina Faso, Chad, and Mali – also known as "Cotton-4" have been the leading protagonist for the reduction of US cotton subsidies through negotiations. The four introduced a "Sectoral Initiative in Favour of Cotton", presented by Burkina Faso's President Blaise Compaoré during the Trade Negotiations Committee on 10 June 2003. Question: What are the African countries of Benin, Burkina Faso, Chad, and Mali referred to as in the cotton industry?
Example Output: Cotton-4

Example Input: Passage: During the Neolithic Era, before the onset of desertification, around 9500 BCE the central Sudan had been a rich environment supporting a large population ranging across what is now barren desert, like the Wadi el-Qa'ab. By the 5th millennium BCE, the people who inhabited what is now called Nubia, were full participants in the "agricultural revolution", living a settled lifestyle with domesticated plants and animals. Saharan rock art of cattle and herdsmen suggests the presence of a cattle cult like those found in Sudan and other pastoral societies in Africa today. Megaliths found at Nabta Playa are overt examples of probably the world's first known archaeoastronomy devices, predating Stonehenge by some 2,000 years. This complexity, as observed at Nabta Playa, and as expressed by different levels of authority within the society there, likely formed the basis for the structure of both the Neolithic society at Nabta and the Old Kingdom of Egypt. Question: During what era was the central Sudan rich in environment?
Example Output:
Neolithic Era