Answer :
To convert milliliters to liters, remember that
$$1 \text{ liter} = 1000 \text{ milliliters}.$$
Thus, to convert $210$ milliliters to liters, you divide by $1000$:
$$
210 \text{ milliliters} = \frac{210}{1000} \text{ liters} = 0.21 \text{ liters}.
$$
So, the answer is $0.21$ liters, which corresponds to option (B).
$$1 \text{ liter} = 1000 \text{ milliliters}.$$
Thus, to convert $210$ milliliters to liters, you divide by $1000$:
$$
210 \text{ milliliters} = \frac{210}{1000} \text{ liters} = 0.21 \text{ liters}.
$$
So, the answer is $0.21$ liters, which corresponds to option (B).
