Baking soda and lemon juice

This task is about fair tests.

Question

Baking soda reacts with lemon juice. Lots of bubbles of gas are given off.
baking soda and lemon juice experiment
You decide to test whether heating the lemon juice speeds up the reaction.
 
Select the experiment below that you should use to test this idea.
    • possible experiment A

    • possible experiment B

    • possible experiment C

    • possible experiment D