What does Marianne Moore mean when she says "imaginary gardens with real toads in them" in this excerpt from "Poetry"?

. . . nor till the poets among us can be
"literalists of
the imagination" —above
insolence and triviality and can present

for inspection, "imaginary gardens with real toads in them," shall
we have
it. . .

a. Poets use abstract concepts because such ideas can be easily understood and make the poem universal.
b. Poets use abstract concepts, so it is hard to determine the meaning of a poem.
c. Poetry is inconsequential because it combines ideas illogically, such as imaginary gardens with real-life objects placed in them.
d. Poets should write at least one poem that includes a pastoral or romantic scene.
e. Poets have the difficult task of incorporating real emotions and facts into the settings they imagine.