The poem Mirror by Sylvia Plath (beautifully) employs allegory, personification, and metaphors. But what can we infer from the title? The title mirror naturally brings to mind ideas of reflection. This is the purpose of a mirror: to reflect. The best answer regarding what we can infer from the title is that the poem may be about self-reflection.
I believe the best answer is the first sentence because that is where the action seems to occur.
The setting is a house at midnight.
I believe a person who manages money is called a treasurer...