Answer:
The figure of speech is personification.
Taking in consideration that prepositional phrases are those that begin with a preposition and end with a noun, pronoun, gerund or clause, the only option that fulfills that criteria is option C. Therefore, this is your best answer.
<span>
the formation of new areeas of oceanic crust which occurs through the magma at ridges and its subsequent outward movement on either side</span>