A Researcher Thinks That a Person's Mood Has an Effect

A researcher thinks that a person's mood has an effect on how helpful that person is likely to be.To test this,the researcher has some research participants come to the laboratory where they are first given a difficult test and then either heavily praised or strongly criticized for their test performance.Afterwards,participants are asked to help the researcher's assistant move some heavy boxes into another room.The researcher makes careful note of how many and which participants help with moving the boxes.In this example,the hypothesis is ________.

A) a person's mood has an effect on how helpful that person is likely to be
B) praise will improve the mood of research subjects and criticism will worsen their mood
C) helping the researcher's assistant will change a participant's mood
D) some participants will be in a better mood than others
E) the difficulty of the test will cause participants to be in a bad mood