C. Personification
At the end of these lines it says that the “taught gut vibrating hummed and sang swallow’s note”. The core is described as humming and singing. These are human qualities. Personification is giving a non-human thing human-like traits. A smilie is a comparison of two things using like it as. There is no like or as in this at all so it is not correct. A metaphor is a comparison of two things without using like or as.