This question investigates which agricultural practices assist in carbon sequestration or storage within the soil, especially concerning global climate change.

Option 1 suggests that Contour bunding and Relay cropping help in carbon storage. Contour bunding is a method of farming that minimizes soil erosion, and relay cropping involves growing two or more crops on the same land in a sequential manner. While both are beneficial agricultural practices, they don`t necessarily contribute to capturing and storing carbon in the soil.

Option 2 suggests that Zero tillage alone aids in carbon storage. Zero tillage is an agricultural technique which increases the amount of organic matter in soil, thereby promoting carbon sequestration.

Option 3 includes all stated practices, but as explained, not all of them assist in carbon sequestration.

Option 4 stating that none of the practices help is incorrect as zero tillage is recognized for helping in carbon storage in soil.

From the explanation, the correct answer is indeed option 2, stating that zero tillage plays a significant role in carbon sequestration.