Marvin,who Lives in San Francisco,has Been Asked to Host a Teenage

Marvin,who lives in San Francisco,has been asked to host a teenage alien,Regor,as part of an intergalactic exchange program.Marvin is sure that Regor would love to experience the adventure of sailing,but decides he should introduce the concept of a "sailboat" first.Marvin tries to describe the common features of a sailboat.He explains that they are pointed at the front and square at the back,have a tall mast to hold up the sail,and have one or two triangular sails.Which of the following demonstrates a problem with this approach?

A) Some sailboats have more than one mast and more than two sails.
B) This description does not describe a specific sailboat.
C) This description does not provide an average of all relevant features.
D) Some sailboats are longer than others.