Static Electricity - Mission SE2 Detailed Help

 Balloons X , Y and Z are suspended from strings as shown below. Positively charged balloon X attracts balloon Y and repels balloon Z. Balloon Y ____. List all that apply in alphabetical order with no spaces between letters.
 Charge Interactions Charged objects show a noticeable interaction with other surrounding objects. The cause of the interaction can be summarized by one of the following three statements: Oppositely charged objects attract each other. Like-charged objects repel each other. Any charged object - whether positive or negative - will attract a neutral object.
 The focus of this question is balloon Y. Balloon Y attracts balloon X - an object of known charge. Using knowledge of the three different types of charge interactions, you can be somewhat conclusive about the type of charge on balloon Y (see Know the Law section).
 When reviewing the three different types of charge interactions (see Know the Law section), you will notice that two of the interaction types involve an attraction of two objects. Oppositely charged objects indeed attract. But that is not the only cause for two objects attracting each other. A charged object and a neutral object will also attract. So knowing that two objects attract each other is NOT sufficient evidence to conclude that both objects are charged. Don't be fooled! If two objects attract, then it is possible that one object is charged and the other is electrically neutral.