You want to continue driving straight ahead. What is correct in this situation?

Your answer is fully correct. In this situation, you want to drive straight ahead at an intersection where a convoy of emergency vehicles is crossing. According to German traffic rules:

You must first allow the convoy to pass through. Emergency vehicles on official missions have priority, and you are required to give way to them.

After you have given way, you must wait at the stop line until it is safe and lawful to proceed. Crossing the junction before the convoy has passed or without stopping would be dangerous and illegal.

Therefore, allowing the convoy to pass and waiting at the stop line ensures you respect the priority of emergency vehicles and follow the traffic regulations correctly. This is why options 1 and 2 are the correct actions in this scenario.