Consider that a mid-point is at equal distances from each end of the line segment.
Given that C is the mid point of AB, so point C must be at equal distance from ends A and B,
[tex]AC=CB[/tex]
Given that AC measures 4 centimeters,
[tex]AC=4\text{ cm}[/tex]
Substitute the value,
[tex]CB=4\text{ cm}[/tex]
Therefore, option A is the correct choice.
