#21.
A bakery owner sells cookies by the dozen. He can bake 3 dozen cookies every hour. The graph shows the linear relationship between y, the number of dozens of cookies baked, and x, the number of hours.
The baker will bake cookies for a total of 8 hours. Which set best represents the domain of the function for this situation?
{0, 1, 2, 3, 4, 5, 6, 7, 8}
\left\{3,\ 9,\ 27,\ 36,\ 44,\ 81\right\}
\left\{1,\ 3,\ 4,\ 21,\ 56,\ 72\right\}
\left\{0,\ 3,\ 6,\ 9,\ 12,\ 15,18,\ 21,\ 24\right\}
\left\{0,\ 1,\ 2,\ 3,\ 4,\ 5,\ 6,\ 7,\ 8\right\}\left\{0,\