The correct answer is option 2: Madam Blavatsky. The Theosophical Society was founded by Helena Petrovna Blavatsky in 1875. She was a Russian occultist and author who played a significant role in the spread of Theosophy, which is a philosophical and spiritual movement. Blavatsky is known for her famous work "The Secret Doctrine," which outlines the principles and ideas of Theosophy. The Theosophical Society aimed to promote the study of comparative religion, philosophy, and science and to investigate hidden and esoteric knowledge. It gained popularity worldwide and had a significant impact on various spiritual and philosophical movements in the late 19th and early 20th centuries.