Final answer:
The correct answer is option 1. The phrase coined by Mark Twain to describe the period between 1865-1900 that is linked to extreme wealth is 'The Gilded Age'. This term refers to economic growth veiling social problems such as deep economic inequality and political corruption.
Step-by-step explanation:
The Gilded Age
The phrase coined by Mark Twain that describes the time period between 1865-1900 and is associated with extravagant wealth is 1) The Gilded Age. The Gilded Age was a time of rapid economic growth and industrialization in the United States, but was also a period known for its ostentatious displays of wealth and deep economic inequalities. Twain's use of the term 'gilded' refers to the practice of covering a base metal with a thin layer of gold; metaphorically, it suggests that the era's overt prosperity and opulence were masking underlying social problems, including political corruption and the exploitation of labor.
The era's name was derived from Twain's 1873 novel, 'The Gilded Age: A Tale of Today', which he co-authored with Charles Dudley Warner. The novel satirizes the corruption of post-Civil War society and the politics of the time. Although Twain and Warner focused on the greed and corruption that pervaded America, it is also important to recognize that this period saw vast improvements in standards of living for many, alongside the growth of industry and even anti-corruption grassroots efforts.