A Researcher Claims That a New Nose Spray, Formula N

Multiple Choice

A researcher claims that a new nose spray, formula N, is far more effective than that in use today, formula O.The null hypothesis should probably focus on

A) the expected performance of her nose spray, formula N.
B) the performance of today's nose spray, formula O.
C) the actual performance of her nose spray, formula N.
D) the difference between her nose spray, formula N, and the one in use today, formula O.