A study of the effect of exposure to color (red or blue) on the ability to solve puzzles used 42 subjects. Half the subjects (21) were asked to solve a series of puzzles while in a red-colored environment. The other half were asked to solve the same series of puzzles while in a bluecolored environment. The time taken to solve the puzzles was recorded for each subject. To compare the mean times for the two groups of subjects using the two-sample t procedures with the conservative Option 2, the correct degrees of freedom is:. (a) 41.
(b) 40.
(c) 20.