The basic unit of meter in poetry is a foot.
Syllable would be the correct answer if the option said 'stressed or unstressed syllable,' because there are two types of syllables, not only the unstressed one. An iamb and a trochee are types of feet in poetry, so they are incorrect as well. A foot is a unit of meter which consists of a number of syllables.
He sees both the extraordinary quality of hope that Gatsby<span> possesses and his idealistic dream of loving Daisy in a perfect world. Though </span>Nick<span> recognizes </span>Gatsby's <span>flaws the first time he meets him, he cannot help but </span>admire Gatsby's<span> brilliant smile, his romantic idealization of Daisy, and his yearning for the future.</span>
The originator of transformational grammar was Noam Chomsky.
