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: 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: West of the Rocky Mountains lies the Intermontane Plateaus (also known as the Intermountain West), a large, arid desert lying between the Rockies and the Cascades and Sierra Nevada ranges. The large southern portion, known as the Great Basin, consists of salt flats, drainage basins, and many small north-south mountain ranges. The Southwest is predominantly a low-lying desert region. A portion known as the Colorado Plateau, centered around the Four Corners region, is considered to have some of the most spectacular scenery in the world. It is accentuated in such national parks as Grand Canyon, Arches, Mesa Verde National Park and Bryce Canyon, among others. Other smaller Intermontane areas include the Columbia Plateau covering eastern Washington, western Idaho and northeast Oregon and the Snake River Plain in Southern Idaho.

SOLUTION: What is the name of the plateau that lies east of the Rocky Mountains?

PROBLEM: Passage: In 1822, the American Colonization Society began sending African-American volunteers to the Pepper Coast to establish a colony for freed African Americans. By 1867, the ACS (and state-related chapters) had assisted in the migration of more than 13,000 African Americans to Liberia. These free African Americans and their descendants married within their community and came to identify as Americo-Liberians. Many were of mixed race and educated in American culture; they did not identify with the indigenous natives of the tribes they encountered. They intermarried largely within the colonial community, developing an ethnic group that had a cultural tradition infused with American notions of political republicanism and Protestant Christianity.

SOLUTION:
In what year did volunteers leave the Pepper Coast?