Read the following  statements and choose the correct option

(I) Flat - beds are used where water availability is adequate and there are no drainage problems.

(II) Where crops are furrow irrigated, raised beds or ridges are essential so that the water can flow down the furrows between them.

(III) Raised beds are usually 10-30 cm high and 100-130 cm wide

(IV) Sunken beds have the exposed sides of raised beds from where considerable moisture can be lost by evaporation.