Answer:
A. [tex]-\frac{1}{2}[/tex]
Step-by-step explanation:
Each mark represent 0.1 unit, so if you count from 0 to [tex]n[/tex] you get 0.5 that is exactly the same that [tex]-\frac{1}{2}[/tex] (for convention the left of the 0 is taken as negative and the right as positive).