A mother consulted the package insert to check the dosage of a medicine she needed to give to her son. In the insert, the following dosage was recommended: 5 drops for every 2 kg of body mass every 8 hours.
If the mother correctly administered 30 drops of the medicine to her son every 8 hours, then his body mass is\\
(A) 12 kg.\\
(B) 16 kg.\\
(C) 24 kg.\\
(D) 36 kg.\\
(E) 75 kg.