The normal body temperature of human beings is commonly considered to be 98.6 °F. However, recent studies have suggested that the average normal body temperature may actually be slightly lower, around 98.2 °F. Option 3, which states that the normal body temperature is 98.4 °F, is the closest answer to the commonly accepted average.

Option 1 (96.4 °F) is too low, and options 2 (97.4 °F) and 4 (99.4 °F) are also slightly off from the commonly accepted average. However, it is important to note that everyone`s body temperature can vary slightly, and what is considered "normal" can depend on various factors such as age, physical activity, and time of day.

Overall, while the provided answer is generally correct, it is important to be aware that individual body temperatures can vary slightly and there is ongoing research on the average normal body temperature.