Step 1: Understand water-soluble vitamins.
Water-soluble vitamins are vitamins that dissolve in water and are not stored in the body. They are easily absorbed and excreted in the urine. The key water-soluble vitamins are B-complex vitamins and Vitamin C.
Step 2: Analyze the options.
- Vitamin E (Option A) is a fat-soluble vitamin.
- Vitamin D (Option B) is a fat-soluble vitamin.
- Vitamin K (Option C) is a fat-soluble vitamin.
- Vitamin B (Option D) is a water-soluble vitamin.
Step 3: Apply to the options.
The correct answer is (D) Vitamin B.
Final Answer:
\[
\boxed{\text{Vitamin B}}
\]