What do we observe on pouring acetic acid on red and blue litmus papers

What do we observe on pouring acetic acid on red and blue litmus papers ?

1. Red litmus remains red and blue litmus turns red.
2. Red litmus turns blue and blue litmus remains blue.
3. Red litmus turns blue and blue litmus turns red.
4. Red litmus becomes colourless and blue litmus remains blue.

Answer

1. Red litmus remains red and blue litmus turns red.