Which of the following is used in lead poisoning?

EDTA

The correct answer is option 1. EDTA

In cases of lead poisoning, the treatment typically involves the use of chelating agents to bind and facilitate the excretion of lead from the body. Among the options provided:

Chelating Agents for Lead Poisoning:

1. EDTA (Ethylenediaminetetraacetic acid):

Used for Lead Poisoning: EDTA is commonly used as a chelating agent in the treatment of lead poisoning. It binds to lead ions, forming a stable complex that can be excreted in the urine. The calcium disodium salt form of EDTA (CaNa2EDTA) is often used for this purpose.
   
2. D-Penicillamine:

Used for Other Metal Poisonings: D-Penicillamine is used primarily for the treatment of Wilson's disease (copper accumulation) and sometimes for rheumatoid arthritis. It is not typically the first choice for lead poisoning.
   
3. Desferrioxamine B:

Used for Iron Overload: Desferrioxamine B is primarily used to treat iron overload conditions, such as those seen in patients with thalassemia who receive frequent blood transfusions. It is not used for lead poisoning.
   
4. Cis Platinic chloride:

Chemotherapy Drug: Cisplatin (cis-diamminedichloroplatinum(II)) is a chemotherapy drug used to treat various cancers. It is not used for treating lead poisoning.

Conclusion: EDTA is the chelating agent specifically used in the treatment of lead poisoning due to its ability to form stable complexes with lead ions and facilitate their excretion from the body.

Therefore, the correct answer is: EDTA.