Step 1: Identify Arya Samaj.
Arya Samaj was a socio-religious reform movement in India, founded in 1875. Its aim was to reform Hindu society and return to the teachings of the Vedas.
Step 2: Founder.
Swami Dayanand Saraswati, a reformer and religious leader, established Arya Samaj in Bombay (now Mumbai).
Step 3: Distinguish from others.
\begin{itemize}
\item Raja Rammohan Roy founded the Brahmo Samaj.
\item Swami Vivekananda founded the Ramakrishna Mission.
\item Mahatma Gandhi led the freedom struggle but was not connected with Arya Samaj.
\end{itemize}
Step 4: Conclusion.
Hence, the correct founder is Swami Dayanand Saraswati.
Final Answer: \[ \boxed{\text{Swami Dayanand Saraswati}} \]
Translate the following passage into English: to be translated
Translate the following into English:
Translate the following passage into English: