The musical sound of Alliteration is the repetition of consonants in the verse so that they could be stressed. In Alliteration, the sounds of the words are same because consonants are repeated in a similar pattern. Alliteration is important for making a poetry musical and allows a rhythm in words which allows easy memorization of poetry.
I think it is A. Natural Sculpture, because your question asks about a type of environment sculpture, so pretty sure it is natural from the environment. Hopefully it is right :)
