The answer to your question is: Â letter A and letter B
Step-by-step explanation:
A Â 1,000 mL = 1 L Â Â This option is correct, there are 1000 ml in 1 liter.
B  1 g = 100 cg      This option is correct, there are 100 cg in 1 gram.
C  1,000 km = 1 m  This option is incorrect, the proportion is 1000 meters in
                 1 kilometer.