**Core Concept**
In salicylic acid poisoning, the body retains CO2 due to respiratory alkalosis, leading to a compensatory metabolic acidosis. This results in a mixed acid-base disorder, characterized by a primary respiratory alkalosis and a secondary metabolic acidosis.

**Why the Correct Answer is Right**
The primary respiratory alkalosis occurs due to the direct stimulation of the respiratory centers by salicylic acid, leading to hyperventilation and a decrease in pCO2. As a result, the pH rises, and the HCO3- levels decrease due to the increased renal excretion of bicarbonate. However, the body's compensatory mechanism involves the retention of CO2, which in turn leads to a decrease in pH, causing a secondary metabolic acidosis. This is reflected in the low HCO3- levels and the low pCO2 in the arterial blood gas analysis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not correctly identify the mixed acid-base disorder seen in salicylic acid poisoning.
**Option B:** This option is incorrect because it only identifies the primary respiratory alkalosis without considering the secondary metabolic acidosis.
**Option C:** This option is incorrect because it only identifies the metabolic acidosis without considering the primary respiratory alkalosis.

**Clinical Pearl / High-Yield Fact**
In mixed acid-base disorders, the primary disorder is usually identified by the primary disturbance in the pH, and the secondary disorder is identified by the compensatory mechanism. In this case, the primary disorder is the respiratory alkalosis, and the secondary disorder is the metabolic acidosis.

**Correct Answer: C. Metabolic acidosis with a compensatory respiratory alkalosis**