Why must one so often rely on allegory and analogy when discussing the soul, according to Plato?

O it was a Greek custom never to speak of God or the soul directly, out of respect for their divinity
O such use of story-telling devices was a habit Plato acquired from listening to Socrates during his youth
O Plato regarded poetic images as more compelling for demonstrating his most important claims than mere arguments
O when attempting to describe metaphysical truths that can only be known imperfectly while the soul is trapped in a body, Plato resorted to such literary devices
O Plato never uses poetic language in discussing philosophical subjects, especially the soul