**Core Concept**
Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. Acquired etiological factors refer to external factors that contribute to the development or exacerbation of ADHD symptoms in individuals who may not have had a predisposition to the disorder.

**Why the Correct Answer is Right**
One possible acquired etiological factor in ADHD is premature birth, particularly those born before 32 weeks of gestation. Premature birth can lead to alterations in brain structure and function, including changes in the prefrontal cortex, which is responsible for executive function and impulse control. This can result in an increased risk of developing ADHD symptoms. Additionally, premature birth is often associated with other risk factors, such as low birth weight, maternal smoking, and exposure to maternal stress, which can further contribute to the development of ADHD.

**Why Each Wrong Option is Incorrect**
**Option A:** Prenatal exposure to lead is not a recognized acquired etiological factor in ADHD. While lead exposure has been linked to cognitive impairment and developmental delays, its relationship to ADHD is more complex and not as well established.

**Option B:** Exposure to secondhand smoke is not a direct cause of ADHD, although it may contribute to other behavioral problems in children.

**Option C:** There is no strong evidence to support the idea that food additives, such as artificial colors or preservatives, are a primary cause of ADHD symptoms. While some studies have suggested a link, the evidence is inconsistent and not conclusive.

**Clinical Pearl / High-Yield Fact**
Premature birth is a significant risk factor for ADHD, particularly in those born before 32 weeks of gestation. This is due to the potential for altered brain development and function, as well as the increased likelihood of other risk factors, such as low birth weight and maternal smoking.

**Correct Answer:** C.