Which of the following types of salt generally contains no iodine?

The correct choice is Himalayan salt, as it typically contains no added iodine. Himalayan salt is harvested from ancient salt deposits, particularly from the Khewra Salt Mine in Pakistan, and it is often marketed as a natural product that is less processed than regular table salt. Because it has not undergone the same refining process that introduces iodine, it usually lacks this essential nutrient.

In contrast, table salt is often iodized, meaning iodine is added during processing to prevent iodine deficiency. This fortification has been a public health measure in many countries. Sea salt may or may not contain iodine, depending on its source and processing, but is more commonly sold without added iodine. Rock salt, like Himalayan salt, typically does not have iodine added, but it often refers to unrefined salts that may contain trace minerals, affecting its iodine content variably.

Thus, while both Himalayan and rock salts generally contain no iodine, Himalayan salt is the most frequently recognized in this context as an unprocessed source of salt without added nutrients.