Triangle ABC is shown on the grid below.
Which value best represents the length of AB?
a 8 units
b 12 units
c 15 units
d 21 units
![Triangle ABC is shown on the grid below Which value best represents the length of AB a 8 units b 12 units c 15 units d 21 units class=](https://us-static.z-dn.net/files/d15/4fc12101bfd205ed8611c44c86d7abbf.png)