Answer: C. 5 units
=================================================
Step-by-step explanation:
Since the x coordinates are the same, we can subtract the y coordinates to get
1.5 - (-3.5) = 1.5 + 3.5 = 5
Note how subtracting a negative is the same as adding.
-------
We can subtract in the other order
-3.5 - 1.5 = -5
but we need to make this result positive. A negative distance is not allowed. Absolute value is applied to make the result positive
|-5| = 5