Test your detective skills

There were tree kids. A teen, a first grader, and a kindergartener. They were at the beach with there mom. The mom went to go get ice cream for them. The teen was on the phone with her boyfriend. The first grader pushed the kindergartener in the water and drowned. The mom came back and was crying. Who is responsible for the kindergarteners death

• Mom

• Teen

• First grader

• Kindergartener