Which lines contain a metaphor?

A"and left behind her, / bead upon bead, / the track of small feet / like dark fern seed."

B"like a queen who walks / down a corridor / the black cat paced / that cold smooth floor—"

C"and the lamplight fell / narrow and thin / a carpet unrolled / for the cat to walk in."

D"Slowly, smoothly, / Black as the night, / with paws unseen / (white upon white)"