A researcher is conducting a study of charitable donations by surveying a simple random sample of households in a certain city. The researcher wants to determine whether there is convincing statistical evidence that more than 50 percent of households in the city gave a charitable donation in the past year. Let p represent the proportion of all households in the city that gave a charitable donation in the past year. Which of the following are appropriate hypotheses for the researcher?

a. H_o : p=0.5 and H_a:p>0.5
b. H_o:p=0.5 and H_a:p≠0.5
c. H_o:p=0.5 and H_a:p<0.5
d. H_o:p>0.5 and H_a:p≠0.5
e. H_o:p>0.5 and H_a:p=0.5