When performing the formalin-ethyl acetate concentration, centrifuge at 500 × g _____.

(a) For 2 minutes on both of the centrifuge spins
(b) For 2 minutes on the first centrifuge spin and 10 minutes on the second spin
(c) For 10 minutes on the first centrifuge spin and 2 minutes on the second spin
(d) For 10 minutes on both of the centrifuge spins