The correct option is C If female is fertile and unfavourable environment for fertilization but favorable for implantation
Embryo transfer (ET) and zygote intra fallopian transfer (ZIFT) can be used to treat many types of infertility. In these methods, the zygote or early embryos are transferred into the fallopian tube. ZIFT-ET is usually applied if female is fertile and has unfavourable environment for fertilization but has favorable conditions for implantation.