The rollers ideally suited for cohesive soils are

Explanation 

Sheep Foot Roller:

• It is best suited for compacting cohesive soils like clay and silty clay.
• The roller has projecting feet (or lugs) that penetrate and knead the soil, breaking up clods and enhancing moisture distribution.
• This kneading action is highly effective in reducing air voids in plastic soils, leading to higher compaction.

 Additional Information

Vibratory Roller:

• Best suited for granular soils like sand and gravel.

• Uses vibration to rearrange soil particles into a denser configuration.

• Ineffective in cohesive soils due to their plastic nature.

Smooth Wheeled Roller:

• Used mainly for finishing surface layers and for granular base or sub-base layers.

• Not effective in compacting cohesive soils as it lacks penetration and kneading action.

Pneumatic Roller:

• Suitable for subgrades and bituminous layers.

• Offers some compaction for cohesive soils, but less effective than sheep foot rollers.

• Works well when combined with water sprinkling on cohesive materials.