Which sentence does not contain any punctuation errors?



A.
It would be fun, I think, to go up in a hot-air balloon.


B.
It would be fun, I think to go up in a hot-air balloon.


C.
It would be fun I think, to go up in a hot-air balloon.


D.
It would be fun I think to go up in a hot-air balloon.
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A or C, i think. plz help