The correct answer is option 3: Vitamins.

Beri-beri is a disease that is caused by a deficiency of certain vitamins, specifically thiamine (vitamin B1). Thiamine plays an important role in the metabolism of carbohydrates, which are the main source of energy for the body. Without enough thiamine, the body is unable to properly convert carbohydrates into energy, leading to symptoms such as muscle weakness, fatigue, and nerve damage.

Option 1: Fats are not directly related to the cause of beri-beri. While fats are an essential nutrient for the body, a deficiency in fats alone would not cause this particular disease.

Option 2: Water is essential for overall health and hydration, but a lack of water would not directly cause beri-beri. Beri-beri is specifically related to a deficiency in certain vitamins.

Option 4: Minerals, similar to fats and water, are important for overall health but are not directly associated with the cause of beri-beri.

Therefore, the correct option is 3, as beri-beri is caused by a deficiency of vitamins, particularly thiamine.