Which of the following statements are normative?$1.$ Air travel has increased since September $112.$ Most iPods are purchased by teenagers$3.$ Every house should have a pet$4.$ Canada should cut its importsA. statements $3$ and $4$ are normativeB.statements $1$ and $2$ are normativeC.statements $2$ and $3$ are normative D$.$ statements $1$ and $4$ are normative