What are two phases during which the moon appears as only tiny silver?

What ideal of imagist poetry is best reflected in this poem by ezra pound in which he compares a crowded metro station to a flowering tree branch? in a station of the metro the apparition of these faces in the crowd; petals on a wet, black bough. a. poetry should be about urban subjects and ideas. b. old poetry should be rewritten in a modern style. c. poets should be able to describe ordinary subjects in new ways. d. poets should write about new subjects with conventional techniques.