Graphene is frequently in news recently. What is its importance? [IAS Prelim] 1. It is a two-dimensional material and has good electrical conductivity. 2. It is one of the thinnest but strongest materials tested so far. 3. It is entirely made of silicon and has high optical transparency. 4. It can be used as 'conducting electrodes' required for touch screens, LCDs and organic LEDs. Which of the statements given above are correct?

• A. 1 and 2 only   
• B. 3 and 4 only
• C.  motor
• D. 1, 2, 3 and 4