Barium carbonate and aluminum phosphate are generally used in:

Correct option is A

The correct option is (a) Rodenticide. Barium carbonate and aluminum phosphate are commonly used as rodenticides to control rodents. These chemicals are toxic to rodents and are used in bait formulations to kill them.
(b) Fumigant A fumigant is a volatile, poisonous substance used to kill insects, nematodes, and other pests that damage stored goods, dwellings, clothing, and nursery stock by releasing toxic gases
(c) Acaricide An acaricide is a substance used to kill or control ticks and mites, which are members of the arachnid subclass Acari, and are used in both medicine and agriculture. 
(d) Fungicide are pesticides that kill or prevent the growth of fungi and their spores. They can be used to control fungi that damage plants, including rusts, mildews and blights. 
(e) Herbicide Herbicides are chemicals used to manipulate or control undesirable vegetation