Safe Operation of a Centrifuge Includes (Check All That Apply)

Safe operation of a centrifuge includes (check all that apply)
i. centrifuging only one specimen at a time
ii. ensuring that specimens are balanced
iii. opening the lid before the centrifuges is completely stopped
iv. cleaning any spills and calibrating on a regular basis

A) i and ii
B) ii and iv
C) i and iii
D) ii and iii