“Satyameva Jayate” means
\[
\text{Truth Alone Triumphs}
\]
This famous phrase is taken from the Mundaka Upanishad, one of the principal Upanishads of ancient Indian literature.
The complete verse is:
\[
\text{Satyameva Jayate Nanritam}
\]
which conveys that truth alone ultimately prevails over falsehood.
The phrase was adopted as the national motto of India and appears below the State Emblem of India.
Therefore,
\[
\boxed{\text{Mundaka Upanishad}}
\]
is the correct answer.
Hence,
\[
\boxed{(B)}
\]