The center of data of histogram is the median and/or mean of the data.The center of a distribution is the middle of any data.
when the data is skewed, the median is more appropriate to use as the measure of a typical value.
Mean is used as the measure of center when the data is symmetric.
In the given Histogram the data is skewed and so Median describe the center of the data in the histogram.
Option C- median is the right answer.