(a) Contour
(b) Ring basin
(c) Check basin
(d) Border strip

Ans. (a) : Contour

Explanation:

Contour farming is adopted in hilly areas where the land has steep slope. Here, the land is divided into series of horizontal strips which are known as terraces. Small bounds are provided at the end of each terrace to held water up to the required depth. Controlled flooding are sub-divided into following types–
• Free flooding
• Basin method
• Check flooding
• Border flooding
• Zig-Zag method