Sami Schmitt Believes That Number of Cars Arriving at His

Sami Schmitt believes that number of cars arriving at his Scrub and Shine Car Wash follow a Poisson distribution. He collected a random sample and constructed the following frequency distribution to test his hypothesis. The number of degrees of freedom for this goodness-of-fit test is _______.

A) 5
B) 4
C) 3
D) 2
E) 1