Convert 2500 milligrams to grams.

To convert milligrams to grams, it is important to remember the relationship between these two units: 1 gram is equal to 1000 milligrams. Therefore, to convert milligrams to grams, you divide the number of milligrams by 1000.

In this case, you have 2500 milligrams. To find out how many grams this represents, you perform the following calculation:

2500 mg ÷ 1000 = 2.5 g

Thus, 2500 milligrams is equivalent to 2.5 grams. This demonstrates the correct conversion from milligrams to grams based on the established metric system relationship, confirming that option B is the right choice.