Five thousand of the 50, 000 books published in country Z in 1991 were novels. Exactly 25 of the films released in country Z in 1992 were based on those novels. Since 100 films were released in country Z in 1992, no more than one-quarter of them were based on books published in country Z in 1991. Which one of the following, if assumed, allows the conclusion above to be properly drawn? ['Some of the films released in 1991 in country Z were based on novels that were published in 1991.', 'None of the films released in country Z in 1992 were based on books other than novels.', 'None of the books that were published in country Z in 1992 were based on plots of films released in 1991.', 'Some of the films released in country Z in 1992 were based on older films that had been released for the first time many years earlier.']