The slogan `One State Many Worlds` is associated with Karnataka, making option 3 the correct answer. This phrase captures the diversity of the state in several aspects: geographically, culturally, historically. Karnataka hosts different landscapes from mountains in Coorg to beaches in Gokarna. The state is culturally rich with diverse languages, lifestyles, and traditions in different regions. The historical architecture from different eras lends another layer to its variety.

In contrast, Assam (option 1) is marketed as `Awesome Assam` which highlights its tea gardens, wildlife, and culture. West Bengal (option 2) is known as `Sweetest part of India`, nodding to its dessert `Rosogolla` and cultural richness. For Rajasthan (option 4), `Padharo Mhare Des` is the tagline emphasizing the tradition of hospitality in the state. Each of these states has unique offerings in tourism but `One State Many Worlds` refers specifically to Karnataka.