**Core Concept**
Dementia is a complex neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired daily functioning. Preventable risk factors for dementia are modifiable lifestyle and medical conditions that, if addressed, can reduce the likelihood of developing dementia.

**Why the Correct Answer is Right**
Preventable risk factors for dementia include hypertension, diabetes mellitus, physical inactivity, smoking, and social isolation. These conditions can lead to vascular damage, inflammation, and oxidative stress in the brain, exacerbating neurodegenerative processes. The pathophysiology of dementia involves the accumulation of amyloid beta plaques and tau tangles, which can be influenced by modifiable lifestyle factors such as exercise, diet, and stress management.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because advanced age is a non-modifiable risk factor for dementia, and while it is a significant predictor, it cannot be prevented.
**Option B:** This option is incorrect because genetic predisposition is a non-modifiable risk factor for dementia, and while certain genetic mutations can increase the risk, they are not preventable.

**Clinical Pearl / High-Yield Fact**
The Lancet Commission on dementia prevention, intervention, and care identified nine potential risk factors for dementia, including hypertension, diabetes mellitus, physical inactivity, smoking, social isolation, depression, low education, air pollution, and obesity. Addressing these modifiable risk factors can potentially reduce the global burden of dementia.

**Correct Answer: D.**