Explanation:

Here’s the thing—when it comes to the knowledge portal under Swachh Bharat Mission (SBM) for sharing best practices among districts and states:

- Option 1: Swachh Sangrah 

This is the right one. Swachh Sangrah is the official portal designed specifically to let districts and states swap stories, resources, and strategies that actually work in the field. It’s all about sharing what works so everyone can improve.

- Option 2: Swachh Sankalp

This isn’t the answer. “Sankalp” usually means resolution or pledge. This term is used more for campaigns or oath-taking, not a knowledge-sharing portal.

- Option 3: Swachh Gyan

Sounds plausible—“Gyan” means knowledge—but there’s no such official portal with this name for SBM.

- Option 4: Swachh Abhiyan

“Abhiyan” means campaign. This is just the generic word for the mission itself, not a knowledge-sharing tool.

So, your answer is spot on.