Firstly, you must divide the subject total by 100. This will give you 1%
of your subject. For example, if you are working out 10% of 4,500,
divide 4,500 by 100 and you will have worked out 1% of 4,500---in this
case, 45. Multiply your 1% answer by the percentage you wish to find
out.
I would say C. A and B make no sense, you want to divide the group randomly because you want to test the new medicine. D is a bit more logical than A and B but still can't, because that isn't random.
