What could have caused this?

Looking through my gallery, reminiscing on the past (though one should look towards the future and not so much backwards), I was reminded that about 4 years ago, I stumbled upon an event featuring myself.😑

With full spirit and positivity for a great start to a new year; I glamorously entered the New Year with a fall to my face on the first day back-to-work after the long year-end holidays. Once I stepped foot into the office, I fell almost face flat on the floor at the reception area. I was left with a mark on my forehead as my forehead knocked the tiled floor.....

To be precise, as I walked and slipped, in effort to regain my balance, I tried to grab hold of my surroundings. However, in a split second, my body made contact with the floor and I saw the white tiles inches away from my face. At that split moment, all I could imagine was the damage it may have caused to my face. At that point, I blacked out for a second and thought this is it....

Suddenly I felt my hand being pushed a little and when my eyes opened, I was sitting upright. In a daze, I felt my wrist sore. A new experience for a New Year?

To my colleagues' amusement, this location has been named by one as the crime scene.

Now..the question is...having knocked my forehead to the smoothed surface flooring, what could have caused this marking right smacked center on my forehead.....

A. My handphone - Samsung edge
B. The access card

C. A Starbucks takeaway plastic cup with straw
D. Some particles or the gaps between the tiles

For I am no forensic expert, please do share your thoughts........😎