Club root of crucifers can be controlled by application of

Answer: Option B

Club root of crucifers can be controlled by the application of Lime.
Clubroot is a fungal disease that affects several plants in the cabbage family including cabbages, radishes, mustard and ornamentals such as candytuft. It is caused by the fungus Plasmodiophora brassicae and gets its name from the club-like roots it induces in infected plants.
Since problems are more severe in acid soils (pH 5.0 - 7.0) adding lime to acid soils can help control the disease.