Which is a run-on sentence?

A.
His watch fell behind the couch he couldn't reach it.

B.
His guitar strings broke, so he can't play now.

C.
His toolbox was unlatched, and his tools fell out.

D.
His project was good, yet his presentation was confusing.

This stuff is confusing:/

Question

Which is a run-on sentence?

 A.
His watch fell behind the couch he couldn't reach it.
 
 B.
His guitar strings broke, so he can't play now.
 
 C.
His toolbox was unlatched, and his tools fell out.
 
 D.
His project was good, yet his presentation was confusing.

This stuff is confusing:/

anonymous · Answer

Which sentence would you say, sounds like the narrator is rambling, and there are too many words with no pauses?