Answer: Median
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Step-by-step explanation:
The main cluster of values is somewhere between 650 and 799, as this is where the highest bars are located. The median is somewhere in this region. The mean however is smaller than the median because the outliers to the left that pull on the mean. The outliers pull the mean toward them. Having small outliers will make the mean smaller than it should be. The median is not affected by outliers. Therefore, the median is the best measure of center in this case.
Side note: we consider this distribution to be "skewed to the left" or "negatively skewed" since the left tail is longer than the right tail.