**Core Concept**
The question is testing the understanding of modifiable and non-modifiable risk factors in the context of disease prevention and management. Modifiable risk factors are those that can be altered or changed to reduce the risk of developing a particular disease or condition.

**Why the Correct Answer is Right**
Modifiable risk factors include lifestyle habits, environmental exposures, and certain medical conditions that can be controlled or managed through interventions such as diet, exercise, medication, or behavior modification. Examples of modifiable risk factors include smoking, hypertension, high cholesterol, and diabetes. In contrast, non-modifiable risk factors are inherent or unchangeable, such as age, sex, genetic predisposition, and family history.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a non-modifiable risk factor. Age is a fixed characteristic that cannot be altered or changed.
**Option B:** This option is incorrect because it is a non-modifiable risk factor. Sex is a biological characteristic that determines an individual's gender and is not subject to change.
**Option C:** This option is incorrect because it is a non-modifiable risk factor. Genetic predisposition refers to the inherited tendency to develop a particular disease or condition, which cannot be altered or changed.

**Clinical Pearl / High-Yield Fact**
It is essential to identify and address modifiable risk factors to prevent or manage chronic diseases. By modifying these risk factors, individuals can reduce their risk of developing conditions such as heart disease, stroke, and diabetes.

**Correct Answer: A. Age is a non-modifiable risk factor.**