The correct answer is Option 3: 1, 2, and 3.

Organic Light Emitting Diodes (OLEDs) have several advantages over Liquid Crystal Displays (LCDs), which are commonly used in many devices such as smartphones, televisions, and computer monitors. The advantages of OLED displays over LCDs are as follows:

1. OLED displays can be fabricated on flexible plastic substrates: One of the significant advantages of OLED displays is that they can be fabricated on flexible plastic substrates. This means that OLED displays can be made thinner and lighter than LCD displays, making them ideal for portable devices like smartphones and tablets. Moreover, OLED displays can be curved, and even rolled up, making them suitable for flexible displays.

2. Roll-up displays embedded in clothing can be made using OLEDs: OLED displays are thin and flexible, which makes them an excellent choice for wearable technology. Roll-up displays embedded in clothing are a possibility using OLEDs. This could potentially lead to clothing with displays that can show the wearer`s vital signs, temperature, and other useful information.

3. Transparent displays are possible using OLEDs: OLED displays can be made transparent, making them ideal for use in windows, mirrors, and other surfaces where information can be displayed without blocking the view. Transparent OLED displays have the potential to revolutionize the way we interact with digital information in our environment.

In conclusion, the advantages of OLED displays over LCDs include their flexibility, lightness, thinness, transparency, and suitability for wearable technology. Therefore, the correct answer to the question is Option 3: 1, 2, and 3.