D.
Explanation: The estimate obtained from a sample is more likely to be closer to the actual parameter value of a population when the sample size is larger. This is because larger sample sizes provide more information and reduce the effect of sampling variability.
Among the given options, option D with a sample size of 600 is the largest. Therefore, the estimate obtained from a sample of size 600 is most likely to be closest to the actual parameter value of the population.
So, the answer is D.
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