**Core Concept**
The concept being tested here is the safe limit of alcohol consumption to avoid liver damage. The liver is the primary organ responsible for metabolizing alcohol, and excessive consumption can lead to liver injury, including fatty liver, alcoholic hepatitis, and cirrhosis.

**Why the Correct Answer is Right**
The safe limit of alcohol consumption is typically defined as 1-2 standard drinks per day for men and 0.5-1 standard drink per day for women. This translates to approximately 10-20 grams of pure alcohol per day. The liver can metabolize a limited amount of alcohol per day, and exceeding this limit can lead to liver damage. The liver's capacity to metabolize alcohol is influenced by factors such as age, body weight, and overall health.

**Why Each Wrong Option is Incorrect**
**Option A:** There is no universally agreed-upon "safe" limit of 50 grams of alcohol per day, as this can still lead to liver damage, especially in individuals with pre-existing liver disease.

**Option B:** There is no evidence to support a daily limit of 100 grams of alcohol as safe, as this can lead to significant liver damage and other health problems.

**Option C:** There is no reliable data to support a daily limit of 200 grams of alcohol as safe, and this amount can lead to severe liver damage and other health issues.

**Clinical Pearl / High-Yield Fact**
The "one drink per day" rule of thumb is a useful estimate, but individual tolerance to alcohol can vary greatly. Factors such as body weight, age, and overall health can influence the safe limit of alcohol consumption.

**Correct Answer:** D.