Para responder essa questão, leia o seguinte trecho do poema A Birthday Present, de Sylvia Plath.
What is this, behind this veil, is it ugly, is it beautiful?
It is shimmering, has it breasts, has it edges?
I am sure it is unique, I am sure it is what I want.
When I am quiet at my cooking I feel it looking, I feel it thinking
'Is this the one I am too appear for,
Is this the elect one, the one with black eye-pits and a scar?
Na oração “I am sure it is unique”, o pronome it se refere a que?