This question is incomplete because the name of the poem is not given. Here is the complete question
The Road Not Taken by Robert Frost. Which poetic device defines the roads in the wood?
The correct answer is D. Metaphor has been used to define the two roads in the wood.
Step-by-step explanation
The poem "the road not taken" by Robert Frost speaks about the dificulty of making decitions. In this poem, this idea is explained through a metaphor (Literary resource to express a reality or idea through a different situation or reality) because the author explains there are two roads in a wood and these roads represent two posible choices. Moreover, the author must decide between the two roads or choices. So, the correct answer is D. Metaphor has been used to define the two roads in the wood.