Zero tillage is a practice that significantly contributes to carbon sequestration in soil by minimizing soil disturbance, thereby preserving soil structure and organic matter. This approach enhances the soil's capacity to store carbon over time through increased biodiversity and microbial activity, which convert organic carbon into stable forms. In contrast, contour bunding and relay cropping, while beneficial for soil conservation and crop productivity, do not directly enhance carbon storage in the same manner as zero tillage, making the latter the correct option in the context of effective carbon sequestration strategies.