What can be expected when two or more drugs act synergistically?

Answer: C — The individual effect of each drug is multiplied

Synergistic drugs are drugs that work together to produce an effect greater than the sum of their individual effects. This means that the individual effects of each drug are not simply added together, but rather they amplify each other. Option A is incorrect because synergistic drugs do not cancel each other's effects, but rather enhance them. Option B is also incorrect because the individual effect of each drug is not reduced, but rather increased. Option D is not correct either as there is a significant change expected when drugs act synergistically. The correct answer is C as it accurately describes the outcome when two or more drugs act synergistically.