In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Let me give you an example: Passage: Nearing London, Oliver encounters Jack Dawkins, a pickpocket more commonly known by the nickname the "Artful Dodger", and his sidekick, a boy of a humorous nature named Charley Bates, but Oliver's innocent and trusting nature fails to see any dishonesty in their actions. The Dodger provides Oliver with a free meal and tells him of a gentleman in London who will "give him lodgings for nothing, and never ask for change". Grateful for the unexpected assistance, Oliver follows the Dodger to the "old gentleman's" residence. In this way Oliver unwittingly falls in with an infamous Jewish criminal known as Fagin, the gentleman of whom the Artful Dodger spoke. Ensnared, Oliver lives with Fagin and his gang of juvenile pickpockets in their lair at Saffron Hill for some time, unaware of their criminal occupations. He believes they make wallets and handkerchiefs.
The answer to this example can be: Who believes Fagin's gang make wallets and handkerchiefs?.
Here is why: This question is based on the following sentence in the passage "He believes they make wallets and handkerchiefs". It evaluates the understanding that the pronoun "he" refers to name "Oliver". You can ask questions like this one about most pronouns in a paragraph.

OK. solve this:
Passage: Cotton processing and trading continued to fall in peacetime, and the exchange closed in 1968. By 1963 the port of Manchester was the UK's third largest, and employed over 3,000 men, but the canal was unable to handle the increasingly large container ships. Traffic declined, and the port closed in 1982. Heavy industry suffered a downturn from the 1960s and was greatly reduced under the economic policies followed by Margaret Thatcher's government after 1979. Manchester lost 150,000 jobs in manufacturing between 1961 and 1983.
Regeneration began in the late 1980s, with initiatives such as the Metrolink, the Bridgewater Concert Hall, the Manchester Arena, and (in Salford) the rebranding of the port as Salford Quays. Two bids to host the Olympic Games were part of a process to raise the international profile of the city.
Manchester has a history of attacks attributed to Irish Republicans, including the Manchester Martyrs of 1867, arson in 1920, a series of explosions in 1939, and two bombs in 1992.
On Saturday 15 June 1996, the Provisional Irish Republican Army (IRA) carried out the 1996 Manchester bombing, the detonation of a large bomb next to a department store in the city centre. The largest to be detonated on British soil, the bomb injured over 200 people, heavily damaged nearby buildings, and broke windows 12 mile (800 m) away. The cost of the immediate damage was initially estimated at 50 million, but this was quickly revised upwards. The final insurance payout was over 400 million; many affected businesses never recovered from the loss of trade.
Answer:
What is the name of the group that was responsible for series a of explosions in 1939 in Manchester?