The correct option is C a(iv), b(i), c(iii), d(ii)
Ex-situ conservation is the conservation and maintenance of plant samples outside their natural habitat through different techniques like zoo, captive breeding, aquarium, botanical garden (a collection of living plant), and gene bank.
The herbarium is a quick referral system in taxonomic studies. It is a collection of preserved plant specimens and associated data used for scientific study.
Biological museums are generally set up in educational institutes such as schools and colleges. Museums have collections of preserved plant and animal specimens for study and reference.
Flora contains the actual account of habitat and distribution of plants of a given area.
So, the correct answer is "option C"