Bench terracing sloping outwards are effective only in

Correct option is B

Outward sloping bench terraces are designed to direct surface runoff away from the slope and are most effective in low rainfall regions. In these areas, the risk of erosion is minimal, and retaining more water near the surface aids in moisture conservation. If used in high rainfall zones, this design would increase the risk of soil erosion and nutrient loss, as water would rapidly flow off the surface. Hence, in such areas, inward sloping terraces or bunds are preferred for water retention.