It is popularly believed that a poem has whatever meaning is assigned to it by the reader. But objective evaluation of poetry is possible only if this popular belief is false; for the aesthetic value of a poem cannot be discussed unless it is possible for at least two readers to agree on the correct interpretation of the poem. Which one of the following is an assumption required by the argument? ['Aesthetic evaluation of literature is best accomplished through discussion by more than two readers.', 'If two readers agree about the meaning of a given poem, that ensures that an objective evaluation of the poem can be made.', 'Discussion of a poem is possible only if it is false that a poem has whatever meaning is assigned to it by the reader.', "A given poem can be objectively evaluated only if the poem's aesthetic value can be discussed."]