A group of elementary school students designed a study to find a possible relationship between the number of students absent from school and the overall rate of flu infections in their town. Which of the following is a correct pairing of possible null and alternative hypotheses for this experiment?

• a. The null hypothesis is that as the flu infection rate decreases, the number of students absent from school also decreases. The alternative hypothesis is that as the flu infection rate increases, the number of students absent from school remains the same.
• b. The null hypothesis is that the flu infection rate has no impact on the number of students absent from school. The alternative hypothesis is that as the flu infection rate increases, the number of students absent from school also increases.
• c. The null hypothesis is that as the flu infection rate decreases, the number of students absent from school also decreases. The alternative hypothesis is that as the flu infection rate increases, the number of students absent from school increases.
• d. The null hypothesis is that the flu infection rate has no impact on the number of students absent from school. The alternative hypothesis is that as the flu infection rate increases, the number of students absent from school remains the same.