Which of the following is used in decorating sweets? 

Silver foil 

The correct answer is option 2. Silver foil.

Silver foil, also known as "varak" or "vark," is a thin, edible silver sheet that is commonly used in the decoration of sweets and desserts in many cultures. It is made by pounding and flattening silver into extremely thin sheets, and these sheets are then carefully applied to the surface of various sweets for decorative purposes.

Here is how silver foil is typically used in decorating sweets:

1. Application:  Silver foil is delicately placed on the surface of sweets to enhance their visual appeal. It is often used to cover the top of sweets, giving them a shiny and luxurious appearance.

2. Cultural Significance:  The use of silver foil in sweets is often associated with special occasions, celebrations, and festivals. It is considered a symbol of prosperity and is commonly used in traditional sweets served during weddings, religious ceremonies, and festive events.

3. Edible Nature: Silver foil used for decorating sweets is typically very thin and can be consumed without causing harm. It is tasteless and odorless, and it adds a touch of elegance to the presentation of the sweets.

It's important to note that while silver foil is commonly used in many cultures, there are also variations, such as gold foil, which serves a similar purpose. Both silver and gold foils are examples of edible metallic leaves used to enhance the aesthetic appeal of various food items, particularly sweets and desserts.