In a whisker and box plot, 25% is from the lowest score to the lower quartile .
For future reference , 50% is from the lowest the lowest score to the median. 75% is from the lowest score to the upper quartile. 100% is the lowest score to the highest score.
With that in mind, you look at the value that starts from the lowest score (which is 19) and then you look at the value that is directly below the lower quartile (which is 31)
So, your answer is option a
