Answer : (C) Vitamin B
Step 1 — Recall the two classes of vitamin
Fat-soluble vitamins : A, D, E and K
Water-soluble vitamins : the B-complex group and C
Only vitamin B appears among the options, so it is the answer.
Step 2 — Note the key difference in behaviour
| Fat-soluble (A, D, E, K) | Water-soluble (B, C) |
|---|
| Dissolve in | fat and oils | water |
| Stored in the body ? | Yes — in the liver and adipose tissue | No |
| Excreted in urine ? | No | Yes, readily |
| Must be taken daily ? | No | Yes |
| Excess can be harmful ? | Yes — can accumulate | No |
Step 3 — Explain why water-soluble vitamins must be taken regularly
Because they dissolve in the aqueous body fluids, any excess passes into the blood, is filtered out by the kidneys and leaves in the urine. They cannot accumulate, so a fresh supply is needed every day.
Step 4 — Note the B-complex members and their deficiency diseases
| Vitamin | Name | Deficiency disease |
|---|
| $B_1$ | Thiamine | Beri-beri |
| $B_2$ | Riboflavin | Cheilosis |
| $B_6$ | Pyridoxine | Convulsions |
| $B_{12}$ | Cyanocobalamin | Pernicious anaemia |
Vitamin C (ascorbic acid), the other water-soluble vitamin, causes scurvy when deficient.
