Final Answer:
The given choices correspond to different types of angles. Among these, the correct option is a. Vertical angles.
Step-by-step explanation:
Vertical angles are a specific type of pair of angles formed by the intersection of two lines. They are opposite each other and share a common vertex. Importantly, vertical angles are always congruent, meaning they have equal measures.
Complementary angles add up to 90 degrees, supplementary angles add up to 180 degrees, and "None of the Above" is not applicable here since vertical angles represent a distinct geometric concept. Vertical angles, with their inherent congruence, play a fundamental role in geometry and are a unique feature of intersecting lines.
In conclusion, the correct answer is a. Vertical angles as these angles formed by intersecting lines are always congruent, providing a specific and well-defined geometric relationship.