If a Correlated-Groups T Test and an Independent-Groups T Test

Multiple Choice

If a correlated-groups t test and an independent-groups t test both have df = 16, which experiment used more subjects?

A) Both used the same number of subjects (N = 18) .
B) Both used the same number of subjects (N = 17) .
C) The correlated-groups t test (N = 17) used more subjects.
D) The independent-groups t test (N = 18) used more subjects.