Step 1: Understanding the Concept of Vedanta.
Vedanta literally means "the end of the Vedas," referring to the philosophical teachings contained in the Upanishads. These texts are considered the concluding part of the Vedas and focus on concepts such as Brahman (the ultimate reality) and Atman (the individual soul).
Step 2: Analyzing the Options.
- 1. Aranyaka: Aranyakas are texts related to rituals and sacrifices performed in forest retreats, not directly associated with Vedanta.
- 2. Upanishad: This is correct. The Upanishads are the main texts associated with Vedanta, dealing with metaphysical and spiritual knowledge.
- 3. Samhita: Samhitas are collections of hymns and mantras, not related to Vedanta directly.
- 4. Brahmana: Brahmanas deal with rituals and ceremonies, not philosophical teachings of Vedanta.
Step 3: Conclusion.
The correct answer is 2. Upanishad.
Final Answer:
\[
\boxed{\text{The correct answer is 2. Upanishad.}}
\]