Answer: C) The imagination has no bounds beyond the limit of one's own mind.
Explanation: In the given excerpt of the poem "On Imagination" by Phyllis Wheatley, we can see that the speaker compares imagination to a soaring bird, because the bird, being able to fly, can go up in the sky and see wonders, but also because how high the bird can fly, only depends on its own limits, as well as the imagination has no bounds beyond the limit of one's own mind.