The box plot shows the number of years during which 12 teams have participated in a rugby tournament:

A box plot is titled Years of Participation and labeled Years. Number line from 0 to 10 with primary markings and labels at 0, 5, and 10. The box extends from 2 to 6 on the number line. There is a vertical line at 4. The whiskers end at 0 and 8.

At least how many schools have participated for 6 years or more?

2 schools

3 schools

4 schools

6 schools