In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

[EX Q]: Which KG unit has two identical digits, 55, 26, or 54?, Context: Five nights later, Birmingham was hit by 369 bombers from KG 54, KG 26, and KG 55. By the end of November, 1,100 bombers were available for night raids. An average of 200 were able to strike per night. This weight of attack went on for two months, with the Luftwaffe dropping 13,900 short tons (12,600 t) of bombs. In November 1940, 6,000 sorties and 23 major attacks (more than 100 tons of bombs dropped) were flown. Two heavy (50 short tons (45 t) of bombs) attacks were also flown. In December, only 11 major and five heavy attacks were made.
[EX A]: 55

[EX Q]: What type of equipment is used with liquid oxygen but not other methods of oxygen storage?, Context: Oxygen storage methods include high pressure oxygen tanks, cryogenics and chemical compounds. For reasons of economy, oxygen is often transported in bulk as a liquid in specially insulated tankers, since one liter of liquefied oxygen is equivalent to 840 liters of gaseous oxygen at atmospheric pressure and 20 °C (68 °F). Such tankers are used to refill bulk liquid oxygen storage containers, which stand outside hospitals and other institutions with a need for large volumes of pure oxygen gas. Liquid oxygen is passed through heat exchangers, which convert the cryogenic liquid into gas before it enters the building. Oxygen is also stored and shipped in smaller cylinders containing the compressed gas; a form that is useful in certain portable medical applications and oxy-fuel welding and cutting.
[EX A]: heat exchangers

[EX Q]: What form of communication did Whitehead rarely partake in?, Context: The two volume biography of Whitehead by Victor Lowe is the most definitive presentation of the life of Whitehead. However, many details of Whitehead's life remain obscure because he left no Nachlass; his family carried out his instructions that all of his papers be destroyed after his death. Additionally, Whitehead was known for his "almost fanatical belief in the right to privacy", and for writing very few personal letters of the kind that would help to gain insight on his life. This led to Lowe himself remarking on the first page of Whitehead's biography, "No professional biographer in his right mind would touch him."
[EX A]:
personal letters