A crop scientist spliced genes for disease resistnace into Ti-plasmids and then treated tomato plants with the plasmids. Some parts of some plants resisted the disease, but most of the plants eventually died. The researcher could increase his chances of sucess by :
A. using molecular probes to figure out where to put genes
B. treating single cells and cloning whole plant from the cells
C. using R-plasmids rather then Ti-plasmids to introduce the genes
D. inserting the genes into the cells of a tomato plant with a needle
