Explanation:
The odd one out in this group is option 'A' - Pencil.

Reasoning:
- Pencil: A pencil is a writing instrument that is used to make marks on paper or other surfaces. It is typically made of wood or plastic and contains a graphite or colored lead core. It is not a piece of clothing, unlike the other options in the group.
- Frock: A frock is a type of dress that is typically worn by women or young girls. It is usually loose-fitting and can be made from various fabrics. It is a piece of clothing.
- Shirt: A shirt is a garment that is worn on the upper body. It typically has a collar, sleeves, and buttons down the front. Shirts come in various styles and can be made from different materials. It is a piece of clothing.
- Skirt: A skirt is a garment that is worn by women or girls and covers the lower part of the body. It is usually fastened around the waist and hangs down to various lengths. Skirts can be made from different fabrics and come in different styles. It is a piece of clothing.

Summary:
Based on the given options, the odd one out is 'Pencil' because it is not a piece of clothing like the other options (Frock, Shirt, Skirt).

In order to determine the odd one out, we need to analyze the given options and identify the one that is different from the others. Let's examine each option:
A: Pencil
- A pencil is a writing instrument made of wood or plastic with a graphite or colored lead. It is commonly used for drawing or writing.
B: Frock
- A frock is a type of dress that is typically worn by women or young girls. It is often loose-fitting and has a defined waistline.
C: Shirt
- A shirt is a garment that is worn on the upper body. It typically has a collar, sleeves, and buttons down the front. Shirts can be made of various materials and come in different styles.
D: Skirt
- A skirt is a garment that is worn on the lower body. It is typically a separate piece of clothing from a top or blouse and does not have separate leg coverings.
Based on the analysis of the given options, we can conclude that the odd one out is:
A: Pencil
Explanation:
- The other options (frock, shirt, skirt) are all types of clothing items, whereas a pencil is a writing instrument. This makes the pencil different from the others in terms of its purpose and usage.
In summary, the odd one out among the given options is A: Pencil, as it is not a clothing item like the rest.