A researcher collected data on the weights, in grams, of 40 different samples of a compound. Fifteen samples weighed less than 10 grams. Twelve samples weighed at least 10 grams but no more than 25 grams. The remaining thirteen samples weighed more than 25 grams. Which of the following could be the median weight, in grams, of these 40 samples?
9
18
26
30