What isn't work?

class Student {
    constructor(gpa, credits){
        this.gpa = gpa;
        this.credits = credits;
    }

    stringGPA() {
        return this.gpa.toString();
    }

    get level() {
            if (this.credits > 90) {
                return 'Senior';
            }
      else if (this.credits <= 90 && this.credit >=61) {
                return 'Junior';
            }
      else if (this.credits <= 60 && this.credit >=31) {
                return 'Sophomore';
            }
      else (this.credits <= 30) {
                return 'Freshman';
      }
    }
}

const student = new Student(3.9);