Which of the following substances turns blue litmus paper to red?

I could not remember whether acid, or base turned litmus read. But three answers were bases and one acid.

Tom, I couldn't remember either. But one of the things was not like the others....

Mellie, me too, but if English isn't one's native language learning can forgive a few minor errors in order to get the information across so long as the gist of it is correct. (Somone axing for an expresso in the morning really grinds my gears lol)

Drives me nuts when the grammar is incorrect 🙄

The Litmus Test. The real truth?

Well looks like I am the only one who commented in this qwestion.