The correct option is D Plant pathology
Professor K.C. Mehta is one of the eminent scientists of India. He is known for his contribution in the field of plant pathology. Plant pathology is a branch of science which deals with the study of diseases in plants which are caused by pathogens. Research of Professor K.C. Mehta related to recurrence of rust in the plains of India is most famous. He even worked on black rust of cereals in Cambridge University. From his researches, it has been concluded that Black rust in plains of India spreads from the Himalayas in the North and Nilgiri and Puleny hills in the South.