Not enough information

Steps:

• The question states X and Y are elements, one a non-metal, but provides no specific details about X, Y, or the choices.
• Choices A, B, C, D are blank, making it impossible to evaluate options.
• Without content for the choices, no logical solving path exists.
• Ambiguous query prevents identifying the key idea or verifying C as correct.

Why C is correct:

• Cannot determine; choices undefined.

Why the others are wrong:

• A: Undefined.
• B: Undefined.
• D: Undefined.

Final answer: Not enough information.