Which sentence is a run-on sentence?

A.
John Glenn was an astronaut; he was the first American to orbit Earth.

B.
Sally Ride was the first American woman in space, she was a member of a shuttle crew.

C.
John Glenn first traveled into space in 1962, and he made his second space flight 36 years later.

D.

When John Glenn traveled on the space shuttle Discovery, he was 77 years old.

Question

Which sentence is a run-on sentence?  
 
 

 
 

  

  A. 
  John Glenn was an astronaut; he was the first American to orbit Earth.   
   

 
 

  

  B. 
  Sally Ride was the first American woman in space, she was a member of a shuttle crew.   
   

 
 

  

  C. 
  John Glenn first traveled into space in 1962, and he made his second space flight 36 years later.   
   

 
 

  

  D. 
 
When John Glenn traveled on the space shuttle Discovery, he was 77 years old.

inowalst · Answer

What do you think?

anonymous · Answer

b? I have 5 more questions I hope you can stay to help

inowalst · Answer

@Ravenn I'm not too sure about this one.

anonymous · Answer

@inowalst  I thinks its C. I looked it up online

anonymous · Answer

@inowalst  please help

anonymous · Answer

@adrynicoleb  @inowalst  @iGreen

anonymous · Answer

:(