Final answer:
The compound being dissolved in dichloromethane is the subject in question, and based on the context of a chemical procedure, it is the reactant, indicated as option 3.
Step-by-step explanation:
The student is asking about a particular compound that is dissolved in dichloromethane (DCM), which is a solvent. Based on the given context, it is clear that the 'compound' mentioned is the one being dissolved in DCM as part of a chemical procedure, typically seen in an organic chemistry experiment. When a procedure mentions that '(The compound) was dissolved in dichloromethane,' it's referring to the unnamed substance as the reactant or the material being dissolved, not the solvent itself. Therefore, the correct answer would be that the compound (option 3) is dissolved in dichloromethane.