I'd say the answer is B, 'then soared to the uttermost reaches' - birds soar when they fly high, and it flies 'to the uttermost reaches', which clearly refers to a bird.
This is the sentence that best allows us to infer that the speaker is being described as a bird. This is because the sentence includes some details that are normally associated with birds. The sentence talks about "soaring," which refers to flying upward in the way birds do. Moreover, he also talks about flying towards the "uttermost reaches" which is something a bird would be able to do.
