**Question:** Find the disease by analysing pedigree chart.

A. Autosomal Dominant
B. X-linked Dominant
C. Autosomal Recessive
D. X-linked Recessive

**Core Concept:** A pedigree chart is a visual representation of family relationships and their medical history, which helps in identifying genetic disorders. Genetic disorders are categorized based on the mode of inheritance, which involves studying patterns of inheritance in successive generations.

**Why the Correct Answer is Right:**

Autosomal Dominant inheritance pattern (Answer C) is when a single gene mutation causes the disease, and it can be expressed in both male and female offspring regardless of sex. In this case, affected individuals have one normal copy and one mutated copy of the gene. One common example is Huntington's disease.

**Why Each Wrong Option is Incorrect:**

Autosomal Recessive (Answer D) is characterized by the need for two mutated copies of the gene to express the disease. This pattern affects both males and females equally but does not show up in individuals with only one mutated copy.

X-linked Dominant (Answer B) refers to disorders caused by a mutated X-linked gene. Males have only one X chromosome, whereas females have two X chromosomes, leading to a higher prevalence of the disease in males.

X-linked Recessive (Answer A) is characterized by the need for two mutated X-linked genes for the disease expression. Both males and females can be affected, but the condition is more severe in males due to having only one X chromosome.

**Clinical Pearl:** To make the pedigree chart analysis easier, use colors or symbols to indicate the sex of family members and the presence or absence of the disease. This helps to identify the mode of inheritance and predict the probability of affected individuals in future generations.

In conclusion, the correct answer is Autosomal Dominant (Answer C) as it involves a single mutated gene causing the disease, affecting both males and females, making it easier to identify in a pedigree chart.