In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.
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. Answer: from 17 to 25 September 1944
Example solution: When did the operation during which the 704th dropped supplies to allied troops near Nijmegen begin?
Example explanation: The passage describes the 704th's actions during Operation Market Garden, and the answer specifies when the operation happened.

Problem: Passage: In December 1969, Presley called Porter to ask him to fix the sound for him in the main showroom at the International Hotel (renamed the Las Vegas Hilton two years later); he said he could not hear himself the last time he sang there, and a new run was scheduled for January. Porter went to see Presley's first rehearsal there, and found three stage monitors hanging high above the stage, with only one working. The hotel's engineers did not get the other two to work, so Porter had some of his own Shure Vocal Master loudspeakers brought over from the recording studio. He laid the column loudspeakers on their sides at the front lip of the stage and propped them up to aim at Presley, who was very happy with the result. Presley insisted upon having Porter mix his live show in January even though he was a recording engineer with no previous experience in live sound. Porter quickly learned about acoustic feedback during the first song, but backstage after the show, film stars and musical artists kept complimenting Presley, telling him that Porter's concert sound was "just like the album". Porter mixed Presley's live concerts from then on. Presley paid Porter well for a touring sound engineer; a 1974 contract for nearly two weeks of touring during SeptemberOctober netted Porter $2,600, an amount equivalent to $ in current value. Porter recorded several of these shows in the mid-1970s, released as albums, and witnessed firsthand Presley's physical decline from drug abuse. In 1975, Presley's doctors advised him to exercise more, so he had a racquetball court built at his mansion Graceland. Porter designed and supervised the installation of a powerful high-fidelity Electro-Voice loudspeaker sound system for the racquetball court and an adjoining lounge. On tour, Porter specified the best-sounding, most roadworthy equipment that existed: he used a Midas PRO4 mixing console and UREI equalizers. The tour was supported by Clair Brothers, who supplied all the audio gear and a monitor engineer, Bruce Jackson, who designed a powerful stage monitor system for Presley's show. In August 1977, Porter was changing planes in Boston to fly to Portland, Maine, to mix a Presley concert when he received a phone call informing him that the singer had died. He attended Presley's heavily guarded funeral ceremony at Graceland. Between Presley appearances, Porter also handled sound duties for Ann-Margret in Las Vegas and on the road, under the business name Captain Audio Productions. He consulted on television specials for Ann-Margret and for Bob Hope in 19721973.
Link Information: none Answer: none
Solution: In what year did Porter handle the sound duties for Ann-Margret?