A boy is late by 9 minutes when walking to school at 4 km/h. If he walks at 5 km/h, he arrives 9 minutes early. What is the distance to his school?

• A. 4 km
• B. 5 km
• C. 6 km
• D. 7 km

• 6 km

Please select one of the options to reveal the correct answer.