Archer Middle School has 78 students playing soccer this year. This number is 6 more than 3 times the number of students who played last year. Let n represent the number of students who played last year. Which equation expresses an equality between two different ways of expressing the number of students who are playing soccer this year?

A: n + 6 = 78
B: 3n + 6 = 78
C: n - 6 = 78
D: 3n - 6 = 78