Answer: The correct answer is Option D.
Step-by-step explanation:
Litmus paper is an indicator which is used to detect an acidic or basic solution.
There are 2 litmus paper used: Red litmus paper and blue litmus paper.
1. Red litmus paper: There is no change in color when this litmus paper is dipped in acidic solution but changes to blue when dipped in basic solution.
2. Blue litmus paper: There is no change in color when this litmus paper is dipped in basic solution but changes to red when dipped in acidic solution.
In the question, the litmus paper is first dipped in acidic solution, so the litmus paper is turned red and when the same litmus paper is dipped in basic solution, it will change its color into blue.
Hence, the correct answer is Option D.