Answer:
Step-by-step explanation:
A central angle is defined as
[tex]s= \theta r[/tex]
Where [tex]\theta[/tex] is the angle that subtends the arc [tex]s[/tex], and [tex]r[/tex] is the radius.
So, if the radius is 2 units long, so the measure of the arc AB would be
[tex]AB=68\°(2)=136\°[/tex]
Which means arc AB measures 136°.
Therefore, the right answer is D.