Final answer:
The information provided does not allow us to conclusively determine which of the given statements must be true, as it lacks context regarding the selection process. However, principles of electrical charge indicate that if X and Y attract, they must have opposite charges.
Step-by-step explanation:
From the information provided, it seems that the question relates to the properties of charged objects interacting with each other. Consequently, it is not possible to determine which statement must be true among the options provided without additional context regarding the selection process. However, if we examine the properties of charged particles, certain principles of electricity may provide insight. Charged objects will exhibit attraction or repulsion depending on their charges. Objects with opposite charges attract each other, while objects with the same charge will repel each other. For instance, if X has a positive charge and Y has a negative charge, they would attract each other.
If an experiment observes that X and Y attract, this implies they have opposite charges as stated in the example given. Thus, any statement claiming that X and Y have the same charge would be incorrect.