Answer:

Step-by-step explanation:
Given
Options a, b and c
Required
Points that are reflections across y-axis
The rule of reflection across the y-axis is:

Testing the given options:

Rule: 

This is true, because the actual reflection equals the given reflection

Rule: 


This is not true, because the actual reflection does not equal to the given reflection

Rule: 

This is not true, because the actual reflection does not equal to the given reflection
Hence
is a reflection of each other across y axis