Which one of the following options will cause red litmus to turn blue?

In the acidic solution, the blue litmus paper turns red. In the basic or alkaline solution, the red litmus paper turns blue.

An aqueous solution of baking soda turns red litmus blue because it is slightly basic in nature. It is also used in soda acid fire extinguishers.

Vinegar, Lemon juice and Orange juice are acids so they turn blue litmus red.