For a volume measurement, which option is equivalent to mL?

The correct answer is milliliter. A milliliter (mL) is a unit of volume in the metric system that is commonly used to measure liquids. It is defined as one-thousandth of a liter. This measurement is widely utilized in both medical and veterinary contexts, allowing for precise dosage of medications.

Understanding the other units can provide clarity on why milliliter is the right choice. A carat is a unit of weight used primarily for gemstones, which does not relate to volume. A millimeter, while a metric unit of length, does not measure volume but instead specifies distance. The cubic millimeter is also a unit of volume but is equivalent to one-thousandth of a milliliter, making it much smaller than a milliliter itself. Thus, when identifying a unit equivalent to mL, milliliter stands out as the direct answer.