B} Vector Method
Mitosis is the Asexual Division of Cells So it is not a Right Answer
Surgery" It is not Possible because we can not see D.N.A. without Special Gadgets
Spontaneous Joining is Also a Wrong Answer But I can't tell you Reason So Sorry
Vector Method is the Right Answer Because By Placing DNA Template into Bacteria{Vector} Plasmid , or Virus{Weak or Almost Dead} DNA And Send It to Targeted Cell