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.

Let me give you an example: Passage: The French and Indian War (1754–1763) was the North American theater of the worldwide Seven Years' War. The war was fought between the colonies of British America and New France, with both sides supported by military units from their parent countries of Great Britain and France, as well as Native American allies. At the start of the war, the French North American colonies had a population of roughly 60,000 European settlers, compared with 2 million in the British North American colonies. The outnumbered French particularly depended on the Indians. Long in conflict, the metropole nations declared war on each other in 1756, escalating the war from a regional affair into an intercontinental conflict.
The answer to this example can be: When was the French and Indian War?
Here is why: This question is based on the following sentence in the passage- The French and Indian War (1754–1763) was the North American theater of the worldwide Seven Years' War. It is a common convention to write (start year-end year) beside a historical event to understand when the event happened. You can ask questions like this one about dates, years, other numerals, persons, locations, noun phrases, verb phrases, adjectives, clauses etc. which exist in the paragraph.

OK. solve this:
American Idol became the most expensive series on broadcast networks for advertisers starting season four, and by the next season, it had broken the record in advertising rate for a regularly scheduled prime-time network series, selling over $700,000 for a 30-seconds slot, and reaching up to $1.3 million for the finale. Its ad prices reached a peak in season seven at $737,000. Estimated revenue more than doubled from $404 million in season three to $870 million in season six. While that declined from season eight onwards, it still earned significantly more than its nearest competitor, with advertising revenue topping $800 million annually the next few seasons. However, the sharp drop in ratings in season eleven also resulted in a sharp drop in advertising rate for season twelve, and the show lost its leading position as the costliest show for advertisers. By 2014, ad revenue from had fallen to $427 million where a 30-second spot went for less than $300,000.
Answer:
In which season did American Idol become the costliest show for advertising on television?