Q. Tobacco leaf discs are transferred with Agrobacterium tumefaciens strain containing binary vector (GUS as reporter gene) with selectable marker neo (kanamycin resistance gene) and then regenerated to plants. The plants are kanamycin resistant, but leaf tissues are negative to GUS assay. The explanation is

• (A) The plants are transformed for both genes but GUS gene is turned
• (B) The plants are transformed for only neo gene not the GUS gene
• (C) The plants are not transformed at all, but the development of kanamycin resistance is due to somaclonal variation
• (D) All the above