Your answer would be D, that is, the analogy is the following one: Baking a cake is like completing a chemistry experiment.
An analogy is a comparison between two different things that are similar in order to explain an idea. In the example in question, the comparison is introduced by the preposition like. Baking a cake is a like completing a chemistry experiment in the sense that you mix up the ingredients and then get a completly different result just as when you handle chemicals in the laboratory.