Arduino "buzzerPin" was not declared in this scope hatası

int redPin = 9;
int greenPin = 10;
int bluePin = 11;
int buzzerPin = 7;

void setColor (byte red, byte green, byte blue){
    analogWrite(redPin, red);
    analogWrite(greenPin, green);
    analogWrite(bluePin, blue);
    analogWrite(buzzerPin, buzzer);
}

void setup (){
    pinMode(redPin, OUTPUT);
    pinMode(greenPin, OUTPUT);
    pinMode(bluePin, OUTPUT);
    pinMode(buzzerPin, OUTPUT);
}
void loop (){
    setColor(0, 0, 255);
    digitalWrite(buzzer, HIGH);
    delay(100);
    setColor(255, 0, 0);
    digitalWrite(buzzer, LOW);
    delay(100);
}