In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
One example: Passage: The group was occasionally diverted from strategic missions to carry out air support and interdiction missions. It supported Operation Overlord, the invasion of Normandy by attacking transportation targets, including bridges, along with airfields and strong points in France. On D Day, the squadron and the rest of the 446th Group led the first heavy bomber mission of the day. The 446th aided ground forces at Caen and Saint-Lo during July by hitting bridges, gun batteries, and enemy troops. During Operation Market Garden, the attempt to seize a bridgehead across the Rhine in the Netherlands, the 704th dropped supplies to allied troops near Nijmegen. It struck lines of communications during the Battle of the Bulge. During Operation Varsity in March 1945, it supplied ground and airborne troops near Wesel. The squadron flew its last combat mission on 25 April 1945 against Salzburg, Austria. The group had flown 273 missions and had lost 58 aircraft during the war,
. Link Information: Operation Market Garden was a failed World War II military operation fought in the Netherlands from 17 to 25 September 1944. Question: When did the operation during which the 704th dropped supplies to allied troops near Nijmegen begin?
Solution is here: from 17 to 25 September 1944
Explanation: The passage describes the 704th's actions during Operation Market Garden, and the answer specifies when the operation happened.

Now, solve this: Passage: Allison co-founded D Magazine -- a monthly magazine covering Dallas -- in 1974, with backing from Dallas investor Ray Lee Hunt. In 1981, he and a group of investors purchased Sport Magazine, which they sold in 1984. He went on to found and publish Art & Antiques in 1984. In 1985, Allison was asked by William F. Buckley, Jr. to join the board of directors of the National Review, and in 1980 he became its publisher, succeeding William A. Rusher. In 1981 or 1982 Allison sold his company Allison Publications, publisher of Art & Antiques. In 1993, he resigned as publisher of National Review. In 1995, he and investor Harlan Crow repurchased D Magazine, and in 2001, Allison bought out Crow to become the magazine company's sole owner. In 1993, Allison edited a new edition of The Bible To Be Read As Living Literature, published by Simon & Schuster. He is also the author of Is That In The Bible? (Dell, 1992) and Condemned To Repeat It: History Lessons For Leaders (Viking Penguin, 1998).
Link Information: The first issue was published in October 1974 by its founders, Wick Allison and Jim Atkinson. Question: How many years total has Allison owned D Magazine?
Solution:
Answer: 46