Read the given experimental procedure and answer the questions given below.
 
In four experiments, two test tubes were connected by a delivery tube. The gas produced in the first test tube was transferred into lime water in the second test tube.

Experiment (a): Vinegar + baking soda
Experiment (b): Lemon juice + vinegar
Experiment (c): Vinegar + common salt
Experiment (d): Lemon juice + baking soda

In which experiment(s) did the lime water turn milky?