The first step in preparing the petri dishes is _____.

A. Fill the agar vial to the 50 ml line with boiling water.

B. Fill the agar vial to the 50 ml line with room temperature water.

C. Fill the agar vial to the 20 ml line with boiling water.

D. Fill the agar vial to the 20 ml line with room temperature water.
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