The histogram shows the heights in meters of trees in a certain section of a park.
How many trees are less than 20 meters tall?
Answer: From the given histogram, we clearly see:
There is 1 tree with height less than 8 meters
There are 1 + 2 = 3 trees with height less than 12 meters
There are 3 + 2 = 5 trees with height less than 16 meters
There are 5 + 4 =9 trees with height less than 20 meters.
Therefore, the correct option is B. 9