Which of the following statements are TRUE on DNA delivery methods during plant transformation? P. Single stranded nicks are made in T-DNA border repeat by the VirD1, VirD2 and VirD3 protein complex. Q. virA gene products form the export apptratus on the membrane for the transfer of T-DNA. R. Gold/Tungsten particles are used as microprojectiles in biolistic method. S. Acceleration of DNA-coated microprojectiles is carried out with compressed CO₂.