This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Input: Consider Input: Passage: The San Diego Symphony at Symphony Towers performs on a regular basis and is directed by Jahja Ling. The San Diego Opera at Civic Center Plaza, directed by Ian Campbell, was ranked by Opera America as one of the top 10 opera companies in the United States. Old Globe Theatre at Balboa Park produces about 15 plays and musicals annually. The La Jolla Playhouse at UCSD is directed by Christopher Ashley. Both the Old Globe Theatre and the La Jolla Playhouse have produced the world premieres of plays and musicals that have gone on to win Tony Awards or nominations on Broadway. The Joan B. Kroc Theatre at Kroc Center's Performing Arts Center is a 600-seat state-of-the-art theatre that hosts music, dance, and theatre performances. The San Diego Repertory Theatre at the Lyceum Theatres in Horton Plaza produces a variety of plays and musicals. Hundreds of movies and a dozen TV shows have been filmed in San Diego, a tradition going back as far as 1898.

Output: Who is the director of the San Francisco Symphony?

Input: Consider Input: Passage: The capital city of Windhoek plays a very important role in Namibia's tourism due to its central location and close proximity to Hosea Kutako International Airport. According to The Namibia Tourism Exit Survey, which was produced by the Millennium Challenge Corporation for the Namibian Directorate of Tourism, 56% of all tourists visiting Namibia during the time period, 2012 - 2013, visited Windhoek. Many of Namibia's tourism related parastatals and governing bodies such as Namibia Wildlife Resorts, Air Namibia and the Namibia Tourism Board as well as Namibia's tourism related trade associations such as the Hospitality Association of Namibia are also all headquartered in Windhoek. There are also a number of notable hotels in Windhoek such as Windhoek Country Club Resort and some international hotel chains also operate in Windhoek, such as Avani Hotels and Resorts and Hilton Hotels and Resorts.

Output: What percentage of tourists arrive in Namibia at Hosea Kutako International Airport?

Input: Consider Input: Passage: Double fertilization refers to a process in which two sperm cells fertilize cells in the ovary. This process begins when a pollen grain adheres to the stigma of the pistil (female reproductive structure), germinates, and grows a long pollen tube. While this pollen tube is growing, a haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid (n) sperm cells. As the pollen tube grows, it makes its way from the stigma, down the style and into the ovary. Here the pollen tube reaches the micropyle of the ovule and digests its way into one of the synergids, releasing its contents (which include the sperm cells). The synergid that the cells were released into degenerates and one sperm makes its way to fertilize the egg cell, producing a diploid (2n) zygote. The second sperm cell fuses with both central cell nuclei, producing a triploid (3n) cell. As the zygote develops into an embryo, the triploid cell develops into the endosperm, which serves as the embryo's food supply. The ovary now will develop into fruit and the ovule will develop into seed.
Output: When a pollen tube fertilizes cells in the ovary, what is it called?