Which of the following passages provides the best example of imagery? a. "to what green altar, o mysterious priest, / lead'st thou that heifer lowing at the skies, / and all her silken flanks with garlands dressed? " b. "what men or gods are these? what maidens loath? " c. "thou, silent form, dost tease us out of thought / as doth eternity: cold pastoral! " d. "beauty is truth, truth is all / ye know on earth, and all ye need to know."