The total population is 216. so option D is correct.
The unitary method is a method for solving a problem by the first value of a single unit and then finding the value by multiplying the single value.
Here, 36 is only 1/6 of the population,
then, 36 x 6 = 216
6/6 or one whole of the population which is 216.
Hence, option D is correct.
Learn more about the unitary method;
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