The correct answer is (d) West Bengal.
Arsenic is a naturally occurring element that can be found in groundwater, soil, and air. It is a metalloid that is not essential for human health and can be toxic in small amounts. Arsenic poisoning can cause a variety of health problems, including skin lesions, cancer, and neurological problems.
West Bengal is the state in India with the highest levels of arsenic contamination in groundwater. According to the World Health Organization, an estimated 30 million people in West Bengal are at risk of arsenic poisoning. The contamination is caused by natural geological processes, and it is not possible to remove arsenic from groundwater once it has been contaminated.
The government of West Bengal has taken steps to address the problem of arsenic contamination, including providing safe drinking water to affected areas and educating people about the risks of arsenic poisoning. However, the problem remains a major public health concern.
The other options are incorrect because they are not the states in India with the highest levels of arsenic contamination in groundwater. Haryana, Rajasthan, and Madhya Pradesh do have some areas with arsenic contamination, but the levels are not as high as in West Bengal.