The upper quartile, also known as the 75th percentile, is given by the right edge of the box in a box and whiskers plot. That looks around 11.5
Second choice
FYI, for a box and whiskers plot, the left edge of the left whisker is the minimum, the left edge of the box is the 25th percentile, the middle line is the median (50th percentile), the right box edge is the 75th percentile and the right whisker end is the maximum.