Joe and Mark would like to start a new business selling a product new to the U.S., the Peraves Monotracer. This is a motorcycle-type vehicle that is encased in a sort of shell, so that the rider can ride this product in any kind of weather. Joe and Mark have done a considerable amount of research on this product, and think it would be successful in the U.S. However, they are still concerned about the risk of a new venture and both would like to avoid losing any personal assets. They should organize their firm as a __________.