The green circle shows the cluster. This is where most of the data tends to stay. The smallest x-value is 4 (shown by the vertical pink line) and the largest x-value is 6 (shown by the vertical blue line). As for the y-value: the smallest is shown by the horizontal pink line at 6 and the largest is 9 shown by the horizontal blue line. This means the answer is C.
Hope this helped :)