I would say the third one but i am not so sure about it
When the two comets collided, it was a moment of impact.
The students had a moment of impact in the hallway when they ran into each other.
Headline- The unexpected lies on the 4th floor.
Subheadline- The discovery that will scare us for the rest of our life.
You use apostrophe to show posession like dog's toy or Danica's phone!
