Determine whether the samples are independent or dependent.
A data set includes a systolic blood pressure measurement from each of 40 randomly selected men and 40 randomly selected women.
a. The samples are independent because there is not a natural pairing between the two samples.
b. The samples are dependent because there is not a natural pairing between the two samples.
c. The samples are independent because there is a natural pairing between the two samples.
d. The samples are dependent because there is a natural pairing between the two samples.