Answer:
An Infinite Number
Step-by-step explanation:
Let's say A and D are points (1,0) and (4,0).
Sure, the points (2, 0) and (3, 0) lie between those values, but you can always go further. Between (2, 0) and (3, 0) lies (2.3, 0) and (2.9, 0). Between those two points lies (2.4567887654, 0).
The numbers will always get smaller and smaller, and therefore there will always be an infinite number of points on just a small line.
