Which sentence correctly uses a comma in a complex sentence? 

1. Although it was raining we went outside
2. Although it was raining, we went outside
3. Although, it was raining we went outside
4. Although it was raining; we went outside

 Subordinating conjunctions (although, because, if) starting sentences need commas after dependent clauses (Purdue OWL). Option a omits it; option c breaks “although” incorrectly; option d misuses a semicolon. Reverse the clauses to omit the comma: “We went outside although it was raining.”