A manufacturer uses a machine to fill bags with 12 ounces of chocolate. Once filled, the bags are weighed. The bags are not approved for use if they weigh 0.4 ounces more or less than the needed weight. Write an equation to represent the highest and lowest weights that will be approved for use.

a. |w + 12| = -0.4
b. |w - 12| = 0.4
c. |w + 0.4| = -12
d. |w - 0.4| = 12