Final answer:
Isotretinoin should be dispensed in its original packaging to prevent accidental exposure to teratogens that can cause birth defects in an unborn fetus.
Step-by-step explanation:
The medication that should be dispensed in its original packaging to prevent accidental exposure to an unborn fetus during the filling process is c) Isotretinoin. Isotretinoin, known for its use in treating severe acne, is a well-known teratogen, which means it can cause birth defects. Since it has such a high risk of causing serious birth defects, it is typically managed under a strict distribution program, such as the iPLEDGE program in the United States, which requires controlled dispensing and thorough patient education to prevent pregnancy during its use.