Which one of the following books of ancient India has the love story of the son of the founder of Sunga dynasty?

The correct answer is Malavikagnirnitra (commonly spelled Mālavikāgnimitram).

Step-by-Step Explanation:

1. Historical Context & The Sunga Dynasty:
The Sunga dynasty was founded by Pushyamitra Sunga after overthrowing the Mauryan Empire. His son was Agnimitra, who succeeded him as the second ruler of the Sunga dynasty.

2. Literary Work:
Mālavikāgnimitram is a famous Sanskrit play composed by the renowned ancient Indian poet and playwright Kalidasa. The title itself is a compound word formed from the names of the two chief characters: Mālavikā and Agnimitra.

3. Plot of the Book:
The play narrates the love story of King Agnimitra (the son of the founder of the Sunga dynasty, Pushyamitra Sunga) and Mālavikā, an exiled servant girl who is later revealed to be of royal birth.

4. Analysis of Other Options:
• Swapnavasavadatta: Written by Bhasa, telling the story of King Udayana and Vasavadatta.
• Meghadoota: A lyrical poem written by Kalidasa about a Yaksha sending a message to his lover via a cloud.
• Ratnavali: A Sanskrit drama about the princess Ratnavali and King Udayana, attributed to King Harsha.

Therefore, the book detailing the love story of the son of the founder of the Sunga dynasty is Malavikagnirnitra.