ACT English Practice Question

Read the following excerpt and consider the bolded portion. Which choice makes the sentence most grammatically acceptable? I turn off the gridlocked **highway, onto a stretch of Route 66 that is,** surrounded by arid New Mexico hills.

1. A.No Change
2. B.highway onto a stretch of Route 66, that is,
3. C.highway onto a stretch, of Route 66 that is
4. D.highway onto a stretch of Route 66 that is