Here is a detailed explanation of the matching:

I. Atropine is a drug that is commonly used to dilate the pupil of the eye. It is used in ophthalmology to facilitate eye examinations and surgeries by enlarging the pupil, allowing for better visualization of the interior of the eye.

II. Ether is a chemical compound that has been historically used as a general anaesthetic. It is administered via inhalation and produces a state of unconsciousness, allowing for surgical procedures to be performed without pain or awareness.

III. Nitroglycerine is a medication primarily used for the treatment of heart conditions, particularly angina. It works by relaxing and dilating the blood vessels, thereby improving blood flow to the heart and reducing chest pain associated with angina.

IV. Pyrethrin is a natural insecticide derived from the flowers of certain chrysanthemum plants. It is effective against a wide range of insects, including mosquitoes. Pyrethrin is commonly used for mosquito control to prevent the spread of mosquito-borne diseases.

Therefore, based on their respective uses, the correct matching is:

I. Atropine - (C) Dilation of pupil

II. Ether - (A) Local anaesthesia

III. Nitroglycerine - (B) Heart trouble

IV. Pyrethrin - (D) Mosquito control