Below Is a Sorted Stem-And-Leaf Diagram for the Measured Speeds $=10$

Multiple Choice

Below is a sorted stem-and-leaf diagram for the measured speeds (miles per hour) of 49 randomly chosen vehicles on highway I-80 in Nebraska. The modal class is: stem unit $=10$
leaf unit $=1$
$\begin{array}{rrl}\text { Frequency } & \text { Stem } & \text { Leaf } \\1 & 4 & 9 \\1 & 5 & 5 \\17 & 6 & 01222455556688999 \\19 & 7 & 0111233345666778999 \\7 & 8 & 0133557 \\4 & 9 & 0122 \\4 9&\end{array}$

A) 60 but less than 70.
B) 70 but less than 80.
C) 80 but less than 90.
D) impossible to determine.