It consists of a series of platforms having suitable vertical drops along contours or on suitable graded lines across the general slope of the land.

Correct option is A

The correct answer is (A) Bench terracing

Explanation:
• The question describes a soil and water conservation practice involving land shaping on sloping areas along contour or graded lines.
• In bench terracing, the land is cut into a number of step-like flat platforms with suitable vertical or nearly vertical drops between them.
• These terraces reduce slope length, control runoff velocity, minimize soil erosion, and help retain moisture for crop growth.
• The method is especially suitable for hilly and steep lands where cultivation on natural slopes is difficult.
• The presence of a series of platforms with distinct vertical drops clearly matches the structural features of bench terracing rather than other practices.
• Hence, the description given in the question directly corresponds to bench terracing as a mechanical soil conservation measure.
• Therefore, option A correctly identifies the practice mentioned in the question.

Information Booster:
• Bench terracing is widely adopted in hilly and mountainous regions to conserve soil and water.
• It helps in preventing landslides and improving agricultural productivity on slopes.
• This practice is recommended in watershed management and hill agriculture systems.
• It effectively reduces runoff and soil loss on steep gradients.
• It is commonly used in tea, coffee, and horticultural crop areas.

Additional Knowledge:
• Contour bunding (Option C): It involves construction of earthen bunds along contours on gentle slopes, without forming step-like platforms.
• Sub-soiling (Option B): It is a deep tillage operation to break hard pans and improve root penetration, not a land-shaping practice.
• Strip cropping (Option D): It involves growing crops in alternate strips to reduce erosion, without construction of terraces or platforms.
• Thus, bench terracing best fits the given description of a series of platforms with vertical drops for erosion control.