In a certain population, the two most heavily diagnosed diseases are schistosomiasis and malaria. over the past five years, malaria has accounted for more than half of all disease cases, and schistosomiasis, which accounted for 40% of all disease cases in the community five years ago, accounted for 30% in the past year. which of the following must be true on the basis of the statements above? a) there were fewer cases of schistosomiasis last year than five years ago. b) the percentage of disease cases from malaria has increased over the past 5 years. c) some disease has experienced an increase in the number of its total cases, as long as the total number of disease cases went down by a number less than 30%.d) each year over the past five, malaria has accounted for a larger percentage of disease cases than schistosomiasis. e) if the total number of schistosomiasis cases increased over the past five years, then the total number of disease cases must have increased by more than 30%.