**Core Concept**
The question is testing the understanding of the role of anticoagulants in preventing glycolysis during blood glucose estimation. This is a crucial concept in clinical laboratory testing, where anticoagulants are used to prevent the degradation of glucose by cellular enzymes.

**Why the Correct Answer is Right**
The correct anticoagulant used in estimating blood glucose is **sodium fluoride (NaF)**. Sodium fluoride inhibits the enzyme enolase, which is involved in the glycolytic pathway. By preventing the breakdown of glucose, sodium fluoride ensures accurate measurement of glucose levels in the blood. This is particularly important in conditions where glucose levels are critical, such as in diabetes management.

**Why Each Wrong Option is Incorrect**
* **Option A:** Sodium citrate is an anticoagulant used in coagulation studies, but it does not prevent glycolysis. It chelates calcium ions, which are essential for the coagulation cascade.
* **Option B:** EDTA (ethylenediaminetetraacetic acid) is a chelating agent used as an anticoagulant in blood gas analysis and other tests. However, it does not prevent glycolysis.
* **Option D:** Oxalate is an anticoagulant used in certain coagulation studies, but it is not used in glucose estimation. It works by binding to calcium ions, which are necessary for coagulation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that sodium fluoride is the correct anticoagulant to use when estimating blood glucose levels. Using the wrong anticoagulant can lead to inaccurate glucose measurements, which can have significant clinical consequences.

**Correct Answer:** C. Sodium fluoride (NaF) prevents glycolysis by inhibiting the enzyme enolase.