Which of the following phrases best captures the meaning of reduce in the context of augment?

The phrase that captures the meaning of "reduce" in the context of "augment" is best understood as indicating a change in magnitude or size. The term "augment" means to increase or make something greater, so "reduce" would suggest doing the opposite of enhancing it. The correct choice reflects this relationship, as it indicates an increase in magnitude.

In contrast, the other options do not align effectively with this context. Simplifying instead of enhancing suggests a different type of change, which does not directly relate to the idea of reducing enhancement. The notion of eliminating completely implies a total removal rather than a reduction, which is not synonymous with augmentation. Underestimating value also does not correspond to the idea of increasing or decreasing magnitude; rather, it reflects a misjudgment that doesn't directly connect to the increase or decrease of an entity's size or importance. Thus, the phrase relating to magnitude correctly aligns with the intent behind "reduce" in the context of "augment."