The correct answer is option 2: Solomon Northup. The historical drama film "12 Years a Slave," which won the Best Picture award at the 86th Academy Awards in March 2014, is based on the 1853 memoir of the same name. The memoir was written by Solomon Northup.

It is important to understand that the film is an adaptation of Northup`s memoir, which recounts his own experiences as a free African-American man who was kidnapped and sold into slavery in the United States in the 19th century. The film, directed by Steve McQueen, brings Northup`s powerful story to life on the screen.

Option 1, Steve McQueen, is incorrect. While Steve McQueen did direct the film, he did not write the memoir on which it is based.

Option 3, Brad Pitt, is incorrect. Brad Pitt is one of the producers of the film but did not write the memoir.

Option 4, Matthew McConaughey, is unrelated to the film and memoir.

In summary, the historical drama film "12 Years a Slave" is based on the memoir written by Solomon Northup.