The question pertains to the number of volumes contained in the 1st edition of the Imperial Gazetteer of India. This is a topic related to Library Science, specifically involving the history and contents of significant reference works.

To determine the correct answer, let's examine the publication history of the Imperial Gazetteer of India. The 1st edition of the Imperial Gazetteer of India was published in the late 19th and early 20th centuries. It was designed to be a comprehensive geographical and historical survey of India.

The Imperial Gazetteer of India in its 1st edition consisted of 9 volumes in total. This compendium was an encyclopedic record that compiled extensive data on the Indian subcontinent, catering to interests in geography, history, economics, and social sciences.

Given this information, the correct answer to the question "How many Volumes did the 1st edition of the Imperial Gazetteer of India contain?" is 9 volumes.

Let's now evaluate the options provided:

• 5 volumes: This option is incorrect, as the 1st edition contained more volumes.
• 7 volumes: This option is incorrect, as the 1st edition contained more volumes.
• 9 volumes: This is the correct option as discussed.
• 12 volumes: This option is incorrect, as the 1st edition contained fewer volumes.

Therefore, the correct answer is 9 volumes. Understanding these historical facets of reference works like the Imperial Gazetteer helps in appreciating their importance in the context of Library Science.