Among the substances listed, bleach is the most basic.
- Cola typically has a pH around 2.5 (acidic).
- Baking soda has a pH around 9 (slightly basic).
- Bleach typically has a pH around 12 to 13 (strongly basic).
- Cheese generally has a pH ranging from 4.5 to 5.5 (acidic).
Therefore, the correct answer is c. Bleach.