instruction:
This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
question:
In addition to those actors who have headlined the series, others have portrayed versions of the Doctor in guest roles. Notably, in 2013, John Hurt guest-starred as a hitherto unknown incarnation of the Doctor known as the War Doctor in the run-up to the show's 50th anniversary special "The Day of the Doctor". He is shown in mini-episode "The Night of the Doctor" to have been retroactively inserted into the show's fictional chronology between McGann and Eccleston's Doctors, although his introduction was written so as not to disturb the established numerical naming of the Doctors. Another example is from the 1986 serial The Trial of a Time Lord, where Michael Jayston portrayed the Valeyard, who is described as an amalgamation of the darker sides of the Doctor's nature, somewhere between his twelfth and final incarnation.
answer:
Who played the War Doctor?

question:
Events in America influenced British policy in Canada, where between 40,000 and 100,000 defeated Loyalists had migrated from America following independence. The 14,000 Loyalists who went to the Saint John and Saint Croix river valleys, then part of Nova Scotia, felt too far removed from the provincial government in Halifax, so London split off New Brunswick as a separate colony in 1784. The Constitutional Act of 1791 created the provinces of Upper Canada (mainly English-speaking) and Lower Canada (mainly French-speaking) to defuse tensions between the French and British communities, and implemented governmental systems similar to those employed in Britain, with the intention of asserting imperial authority and not allowing the sort of popular control of government that was perceived to have led to the American Revolution.
answer:
How many British loyalists moved from the US to Canada?

question:
The Portuguese explorer Diogo Cao reached the mouth of the Congo in 1484. Commercial relationships quickly grew between the inland Bantu kingdoms and European merchants who traded various commodities, manufactured goods, and people captured from the hinterlands. After centuries as a major hub for transatlantic trade, direct European colonization of the Congo river delta began in the late 19th century, subsequently eroding the power of the Bantu societies in the region.
answer:
Whose expedition arrived at the mouth of the Congo River in 1484?