In order to find the solution we need to understand that a dosage of 20 mg/kg means that 20 mg are administered to the patient for each kg of his/her weight.
So, if the patient weight is 60 kg then:
Total drug X = (20mg/Kg)*(60Kg)=1200mg.
In conclusion, 1200 mg will be administered to the patient, so the answer is D.
