In 2016, the Centers for Disease Control and Prevention estimated that the flu vaccine was 73% effective against the influenza B virus. An immunologist suspects that the current flu vaccine is less effective against this virus. Pick the correct pair of hypotheses the immunologist could use to test this claim.

i. H_o : p > 0.73
H_a : p < 0.73

ii. H_o: p = 0.73
H_a: p < 0.73

iii. Ho: p = 0.73
Ha: p > 0.73

iv. Ho: p = 0.73
Ha: p ≠ 0.73