Select the most appropriate option to fill in blank no. 2.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. on.
In the sentence, we're discussing the purpose or usage of posters.
The word "on" suggests that posters are used on or upon various surfaces or mediums to convey information. This preposition indicates the location or position of where posters are displayed or utilized.
Hence, the chosen option will be the correct answer.