**Core Concept**
The given patient has a metabolic acidosis with respiratory compensation. The primary disorder is a decrease in bicarbonate levels, leading to an acidotic state. The body attempts to compensate by increasing ventilation, which reduces pCO2 levels.

**Why the Correct Answer is Right**
The patient has a low bicarbonate level (10 meq), indicating a metabolic component to the acid-base disorder. The low bicarbonate level is due to either a loss or a failure to produce bicarbonate. The pCO2 level of 30 mmHg is lower than the normal range (35-45 mmHg), indicating a compensatory increase in ventilation. This compensatory response helps to restore acid-base balance by reducing the amount of CO2, which is a volatile acid.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not account for the low bicarbonate level, which is a key component of the acid-base disorder.
* **Option B:** This option is incorrect because it incorrectly identifies the primary disorder as a respiratory acidosis, when in fact the primary disorder is a metabolic acidosis.
* **Option C:** This option is incorrect because it does not accurately describe the compensatory response to the metabolic acidosis.

**Clinical Pearl / High-Yield Fact**
In acid-base disorders, the primary disorder is often a metabolic component, and the respiratory component is a compensatory response. Always look for the primary disorder and the compensatory response when evaluating acid-base disturbances.

**Correct Answer: C. Metabolic acidosis with respiratory compensation.**