## Core Concept
The safe limit of alcohol consumption varies by gender due to differences in body composition, metabolism, and sensitivity to alcohol. Generally, guidelines recommend that men and women limit their alcohol intake to avoid health risks. The standard drink sizes and recommended limits are often defined by health organizations.

## Why the Correct Answer is Right
The correct answer, , indicates that the safe limit for males is 21 units/week and for females is 14 units/week. This recommendation is based on the risk of alcohol-related health problems. One unit of alcohol is typically defined as 10 ml (or 8 grams) of pure alcohol. This amount is found in approximately half a pint of beer, a small glass of wine, or a single shot of spirits. The differentiation in limits between genders accounts for the generally lower body mass and higher percentage of body fat in women, which influences alcohol distribution and metabolism.

## Why Each Wrong Option is Incorrect
- **Option A:** This option suggests a limit of 14 units/week for both males and females, which underestimates the safe limit for males.
- **Option B:** This option provides a range (14-21 units/week) without specifying gender differences, making it less precise than the correct answer.
- **Option D:** This option suggests higher limits (42 units/week for males and 28 units/week for females), which could increase the risk of alcohol-related health issues.

## Clinical Pearl / High-Yield Fact
A key point to remember is that these limits are general guidelines and can vary depending on individual health status, medication use, and pregnancy status. Additionally, binge drinking and the pattern of consumption are also critical factors in assessing alcohol-related risks.

## Correct Answer: C. 21 units/week for males and 14 units/week for females.