Very small 4 wheeled car question, is it a car or moped?

I am thinking of buying an old BMW Isetta from the 50's/60's, I have the money and I can get a motorcycle license and drive legally but I have to wait 6 months to get a real drivers license and im sick of taking the bus. The Isetta is only 247 cc making it by displacement a moped but has 4 very small wheels so i was wondering if the small engine displacement would make it a moped or does it make it a car with 4 wheels. Thanks for the help!