The population of a city on February 15, 2009, was 36,600. The city has a passive surveillance system that collects hospital and private physician reports of inuenza cases every month. During the period between January 1 and April 1, 2009, 2,200 new cases of inuenza occurred in the city. Of these cases, 705 persons were still ill with inuenza according to surveillance reports on April 1, 2009. The reported prevalence of active inuenza on April 1, 2009, was:

Select one:

a. 320 per 1,000 population

b. 60 per 1,000 population

c. 17.5 per 1,000 population

d. 19 per 1,000 population

e. Cannot be calculated from this data