A study by the Information Technology department at WPU revealed company employees receive an average of four e-mails per hour. Assume the arrival of these e-mails is approximated by the Poisson distribution. (a) What is the probability, Prof. Smith, received exactly one e-mail between 4pm and 5pm yesterday? (b) What is the probability he did not receive any e-mail during this period? (c) What is the probability he received ten or more e-mails during the same period?