Although the abscess was incised and drained in the emergency room and cultures were obtained, which grew coag-positive staphylococcus.

1. This is a run-on that needs a semicolon after drained.
2. This is a run-on that needs to be split into two separate sentences.
3. This is a fragment that can be fixed by adding a comma after incised.
4. This is a fragment that can be fixed by adding a comma after incised.
5. The sentence is fine as it is.
Answer:
4. remove the word although.
otherwise - make it into 2 sentences.

Answers 3 and 4 are the same. You're right that the word "although" should be removed.

None of these answers is correct. The sentence is a fragment because it has two dependent clauses and no independent clause.

The correct answer is: 2. This is a run-on that needs to be split into two separate sentences.

To correct the sentence, it can be split into two separate sentences:

"Although the abscess was incised and drained in the emergency room and cultures were obtained, which grew coag-positive staphylococcus."

Revised:

"Although the abscess was incised and drained in the emergency room and cultures were obtained. The cultures grew coag-positive staphylococcus."