TASK DEFINITION: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
PROBLEM: Passage: The climate in Southeast Alaska is a mid-latitude oceanic climate (Köppen climate classification: Cfb) in the southern sections and a subarctic oceanic climate (Köppen Cfc) in the northern parts. On an annual basis, Southeast is both the wettest and warmest part of Alaska with milder temperatures in the winter and high precipitation throughout the year. Juneau averages over 50 in (130 cm) of precipitation a year, and Ketchikan averages over 150 in (380 cm). This is also the only region in Alaska in which the average daytime high temperature is above freezing during the winter months.

SOLUTION: How much precipitation doesn't Juneau receive each year?

PROBLEM: Passage: Victoria was pleased when Gladstone resigned in 1885 after his budget was defeated. She thought his government was "the worst I have ever had", and blamed him for the death of General Gordon at Khartoum. Gladstone was replaced by Lord Salisbury. Salisbury's government only lasted a few months, however, and Victoria was forced to recall Gladstone, whom she referred to as a "half crazy & really in many ways ridiculous old man". Gladstone attempted to pass a bill granting Ireland home rule, but to Victoria's glee it was defeated. In the ensuing election, Gladstone's party lost to Salisbury's and the government switched hands again.

SOLUTION: What year didn't Gladstone resign?

PROBLEM: Passage: The accession of Valens gave a fresh lease of life to the Arian party. He issued a decree banishing the bishops who had been deposed by Constantius, but who had been permitted by Jovian to return to their sees. The news created the greatest consternation in the city of Alexandria itself, and the prefect, in order to prevent a serious outbreak, gave public assurance that the very special case of Athanasius would be laid before the emperor. But the saint seems to have divined what was preparing in secret against him. He quietly withdrew from Alexandria, 5 October, and took up his abode in a country house outside the city. Valens, who seems to have sincerely dreaded the possible consequences of another popular outbreak, within a few weeks issued orders allowing Athanasius to return to his episcopal see. 

SOLUTION:
 What party didn't benefit from the accession of Valens?