Which revision best corrects the errors in the given sentence?
when you were very small 8–10 pounds, you slept in this cradle.
a.
when you were very small (8–10 pounds), you slept in this cradle.
b.
when you were very small—(8–10 pounds), you slept in this cradle
c.
(when you were very small 8–10 pounds,) you slept in this cradle.