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Answer:
Let's find a number that, when 1/3 is taken and then 1/5 is taken, results in a whole number:
A. 8: (1/3) * 8 = 2.67, not a whole number.
B. 10: (1/3) * 10 = 3.33, not a whole number.
C. 18: (1/3) * 18 = 6, (1/5) * 6 = 1.2, not a whole number.
D. 30: (1/3) * 30 = 10, (1/5) * 10 = 2, a whole number.
So, the number of chocolates Tanmay could have had in the beginning is D. 30.