This could be many things. It's common for young girls you have irregular periods but could also be a health problem. There is also a possibility of pregnancy if she is sexually active.
D. viruses ( why does it have to be 20 characters)
Stone, brush, cars, shovel, clock, robot, pencils, ball, doll, skateboard, cloud and chips. :D
D is the answer. The first 3 are not good communication.
