Which sentence does not contain any errors in comma usage?

A.
In Vienna musicians first played the harpsichord, but then someone invented the piano.

B.
In Vienna musicians first played the harpsichord but, then someone invented the piano.

C.
In Vienna musicians first played the harpsichord but then someone invented the piano.

D.
In Vienna musicians first played the harpsichord, but, then someone invented the piano.

Question

Which sentence does not contain any errors in comma usage?
 
 A.
In Vienna musicians first played the harpsichord, but then someone invented the piano.
 
 B.
In Vienna musicians first played the harpsichord but, then someone invented the piano.
 
 C.
In Vienna musicians first played the harpsichord but then someone invented the piano.
 
 D.
In Vienna musicians first played the harpsichord, but, then someone invented the piano.

gabbyalicorn · Answer

Hello! Fellow brony/ pegisister! I will help you on this.

anonymous · Answer

What do you think the answer is?

anonymous · Answer

i have no idea

gabbyalicorn · Answer

All of the sentences contain an error in comma usage because there should be a comma after "Vienna" and before "musicians".

anonymous · Answer

@gabbyalicorn is correct.

anonymous · Answer

Which means the answer is "In Vienna musicians first played the harpsichord but, then someone invented the piano."

anonymous · Answer

At least, that is what I think it is.

anonymous · Answer

so b or d

anonymous · Answer

sorry i mean b

anonymous · Answer

@baytotheocean Yes, B.