Final answer:
The population that would most benefit from taking a regular multivitamin and mineral supplement is children under the age of five.
Step-by-step explanation:
The population that would most benefit from taking a regular multivitamin and mineral supplement is d) Children under the age of five.
The reason for this is that young children have developing bodies and may not always get all the necessary vitamins and minerals from their diet alone. A multivitamin supplement can help ensure that they receive adequate nutrients for proper growth and development.
It is important to note that for individuals with well-balanced diets, a multivitamin supplement is typically not necessary as they are already receiving all the necessary nutrients from their food.