The correct answer is A) salt water feed heater. In a flash evaporator, the salt water feed heater is the most likely component where scale will occur due to higher than normal temperatures. This is because the feed heater is responsible for increasing the temperature of the salt water feed, which can lead to the precipitation of dissolved salts and the formation of scale on the heat transfer surfaces. The other options are less likely to experience scale buildup due to higher temperatures. The second stage vapor separator, distillate cooler, and second stage feed heater do not directly experience the same high-temperature conditions as the salt water feed heater, which is the primary source of the elevated temperatures that can cause scale formation.