What story should I write?

I would like to either write a story or continue writing a story. But my problem is, what should I write? Should I write a fantasy story about people with elemental powers? Or should I write a realistic fiction story about a 12 year old going into 8th grade? Should I write a romance about a teenage boy, his girlfriend, and a zombie apocalypse? Or should I write a science fiction about life on a futuristic alien ship? Please help!