Burns that have a 'water line' or sharp demarcation border are known as:

Immersion burns are defined by a sharp demarcation border, often resembling a "water line" due to the specific distribution of heat in contact with the skin. This distinguishes them from friction burns, which are the result of rubbing or scraping against a rough surface. Chemical burns typically have a different appearance, often causing discolored or blistered skin in the area of contact. Electrical burns may have a different distribution of tissue damage, as well as other unique symptoms such as muscle contractions or respiratory issues. Therefore, option B is the most accurate answer in this scenario.