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.

Passage: Season ten of the series premiered on January 19, 2011. Many changes were introduced this season, from the format to the personnel of the show. Jennifer Lopez and Steven Tyler joined Randy Jackson as judges following the departures of Simon Cowell (who left to launch the U.S. version of The X Factor), Kara DioGuardi (whose contract was not renewed) and Ellen DeGeneres, while Nigel Lythgoe returned as executive producer. Jimmy Iovine, chairman of the Interscope Geffen A&M label group, the new partner of American Idol, acted as the in-house mentor in place of weekly guest mentors, although in later episodes special guest mentors such as Beyoncé, will.i.am and Lady Gaga were brought in. Question: Who replace weekly mentors as a more permanent mentor on American Idols tenth season? 
Jimmy Iovine

Passage: Returning to the basic concept of current flows in a conductor, consider what happens if a half-wave dipole is not connected to a feed point, but instead shorted out. Electrically this forms a single 1⁄2-wavelength element. But the overall current pattern is the same; the current will be zero at the two ends, and reach a maximum in the center. Thus signals near the design frequency will continue to create a standing wave pattern. Any varying electrical current, like the standing wave in the element, will radiate a signal. In this case, aside from resistive losses in the element, the rebroadcast signal will be significantly similar to the original signal in both magnitude and shape. If this element is placed so its signal reaches the main dipole in-phase, it will reinforce the original signal, and increase the current in the dipole. Elements used in this way are known as passive elements. Question: What is a half wave dipole need to be coupled with in most instances?
feed point

Passage: Following the fall of Wu and the turmoil of the Wu Hu uprising against the Jin dynasty (265–420), most of elite Chinese families had collaborated with the non-Chinese rulers and military conquerors in the north. Some may have lost social privilege, and took refugee in areas south to Yangtze River. Some of the Chinese refugees from north China might have resided in areas near Hangzhou. For example, the clan of Zhuge Liang (181–234), a chancellor of the state of Shu Han from Central Plain in north China during the Three Kingdoms period, gathered together at the suburb of Hangzhou, forming an exclusive, closed village Zhuge Village (Zhege Cun), consisting of villagers all with family name "Zhuge". The village has intentionally isolated itself from the surrounding communities for centuries to this day, and only recently came to be known in public. It suggests that a small number of powerful, elite Chinese refugees from the Central Plain might have taken refugee in south of the Yangtze River. However, considering the mountainous geography and relative lack of agrarian lands in Zhejiang, most of these refugees might have resided in some areas in south China beyond Zhejiang, where fertile agrarian lands and metropolitan resources were available, mainly north Jiangsu, west Fujian, Jiangxi, Hunan, Anhui,and provinces where less cohesive, organized regional governments had been in place. Metropolitan areas of Sichuan was another hub for refugees, given that the state of Shu had long been founded and ruled by political and military elites from the Central Plain and north China. Some refugees from the north China might have found residence in south China depending on their social status and military power in the north. The rump Jin state or the Southern Dynasties vied against some elite Chinese from the Central Plain and south of the Yangtze River. Question: What kind of geography is in Zhejiang?

mountainous