Correct Answer - Option 2 : Interference
Digital paper: It is also known as interactive paper, is the patterned paper used in conjunction with a digital pen to create handwritten digital documents.
The printed dot pattern uniquely identifies the position coordinates on the paper. The digital pen uses this pattern to store the handwriting and upload it to a computer.
Basically it involves the Interference phenomenon in it to store the optical data collected through the digital paper.
