**Core Concept**
Sub-acute toxicity studies are conducted to evaluate the safety profile of a drug when administered at doses higher than those used in therapeutic settings, but lower than those that would cause severe adverse effects. This helps in identifying potential toxic effects and establishing a no-observed-adverse-effect level (NOAEL) for the drug.

**Why the Correct Answer is Right**
Sub-acute toxicity studies typically involve administering the drug to animals for 14-30 days, which allows for the assessment of potential adverse effects that may not be apparent in acute toxicity studies. During this period, the drug's pharmacokinetics and pharmacodynamics are evaluated, and its effects on various organs and systems are monitored. This helps in understanding the drug's potential for causing harm and identifying the dose at which adverse effects become apparent.

**Why Each Wrong Option is Incorrect**
**Option A:** Acute toxicity studies involve shorter durations of drug administration (typically up to 14 days) and are designed to identify severe adverse effects that occur shortly after exposure.
**Option B:** Chronic toxicity studies involve longer durations of drug administration (typically 30 days to 2 years) and are designed to identify potential long-term adverse effects.
**Option C:** Teratogenicity studies involve administering the drug to pregnant animals to evaluate its potential for causing birth defects.

**Clinical Pearl / High-Yield Fact**
When designing animal studies to evaluate the safety of a new drug, it's essential to consider the duration of exposure and the species used, as these factors can significantly impact the results and inform human safety evaluations.

**Correct Answer: C. 14-30 days**