**Core Concept**
The question pertains to the management of forearm fractures, specifically the positioning of the arm in a plaster cast to facilitate healing and prevent complications. The correct positioning is crucial to minimize the risk of nerve injury, promote proper bone healing, and avoid malunion or nonunion.

**Why the Correct Answer is Right**
In cases of bilateral forearm fractures at the same level, it is essential to position the arm in a way that allows for proper alignment and immobilization. The position of choice is typically with the forearm in mid-pronation and the wrist in a neutral position. This positioning helps to minimize the risk of nerve injury, particularly to the median and ulnar nerves, which run through the forearm. By keeping the wrist in a neutral position, the cast can be applied without compromising the nerve function.

**Why Each Wrong Option is Incorrect**
* **Option A:** This position is incorrect as it may lead to nerve compression and compromise the healing process. The wrist should not be flexed or extended, as this can cause nerve damage.
* **Option B:** Pronation of the forearm is not ideal in this scenario, as it may lead to malunion or nonunion of the fractures. The correct position is mid-pronation.
* **Option D:** This position is incorrect as it may cause nerve compression and compromise the healing process. The wrist should not be flexed or extended, as this can cause nerve damage.

**Clinical Pearl / High-Yield Fact**
Remember the "PROM" rule for forearm fractures: Position the forearm in mid-pronation, Rotate the wrist to a neutral position, and Maintain a stable cast to prevent complications.

**Correct Answer:** C.