Graphing dice throws

This task is about the best type of graph to show different data.
a)  Sivendra threw a dice 50 times and wrote down the number that was facing up after each throw.

  What kind of graph would be best to display this data?
 
  (A)
(B)
(C)
(D
Bar graph
Line graph
Box-and-whisker graph
Stem-and-leaf graph
 
 
b)  Petra chose a histogram to graph the heights of people in her younger sister's class.

  Why is a histogram the best kind of graph to display this type of data?