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.

Ex Input:
Passage: The UAP had been formed as a new conservative alliance in 1931, with Labor defector Joseph Lyons as its leader. The stance of Lyons and other Labor rebels against the more radical proposals of the Labor movement to deal the Great Depression had attracted the support of prominent Australian conservatives. With Australia still suffering the effects of the Great Depression, the newly formed party won a landslide victory at the 1931 Election, and the Lyons Government went on to win three consecutive elections. It largely avoided Keynesian pump-priming and pursued a more conservative fiscal policy of debt reduction and balanced budgets as a means of stewarding Australia out of the Depression. Lyons' death in 1939 saw Robert Menzies assume the Prime Ministership on the eve of war. Menzies served as Prime Minister from 1939 to 1941 but resigned as leader of the minority World War II government amidst an unworkable parliamentary majority. The UAP, led by Billy Hughes, disintegrated after suffering a heavy defeat in the 1943 election. Question: What years did Robert Menzies serve as Prime Minister?

Ex Output:
1939 to 1941

Ex Input:
Passage: The PermianTriassic extinction event, which was a prolonged event due to the accumulation of several extinction pulses, ended the dominance of the carnivores among the therapsids. In the early Triassic, all the medium to large land carnivore niches were taken over by archosaurs which, over an extended period of time (35 million years), came to include the crocodylomorphs, the pterosaurs, and the dinosaurs. By the Jurassic, the dinosaurs had come to dominate the large terrestrial herbivore niches as well. Question: What was the name of extinction level event that ended the dominance of the carnivores among therapsids?

Ex Output:
PermianTriassic

Ex Input:
Passage: London's bus network is one of the largest in the world, running 24 hours a day, with about 8,500 buses, more than 700 bus routes and around 19,500 bus stops. In 2013, the network had more than 2 billion commuter trips per annum, more than the Underground. Around 850 million is taken in revenue each year. London has the largest wheelchair accessible network in the world and, from the 3rd quarter of 2007, became more accessible to hearing and visually impaired passengers as audio-visual announcements were introduced. The distinctive red double-decker buses are an internationally recognised trademark of London transport along with black cabs and the Tube. Question: What feature added in 2007 facilitated bus travel by London' passengers with hearing and vision impairments?

Ex Output:
audio-visual announcements