**Core Concept**
The mid-day meal program in schools aims to improve the nutritional status of school-going children. Enhancing the nutritious value of these meals is crucial for their growth, development, and academic performance.

**Why the Correct Answer is Right**
Incorporating a variety of nutrient-dense foods in the mid-day meal program can significantly improve its nutritional value. This can be achieved by including protein-rich foods like pulses, dairy products, and nuts; whole grains like brown rice, whole wheat, and millets; and a mix of colorful vegetables and fruits. These foods provide essential vitamins, minerals, and fiber, which are vital for children's growth and development.

**Why Each Wrong Option is Incorrect**
**Option A:** Inadequate protein intake can lead to growth retardation and impaired cognitive development in children. Therefore, including protein-rich foods in the mid-day meal program is essential.
**Option B:** While whole grains are a good source of fiber, they are not the only option for improving the nutritious value of the mid-day meal program. A variety of nutrient-dense foods should be included.
**Option C:** Fruits and vegetables are essential for providing essential vitamins and minerals, but they are not the sole solution for improving the nutritious value of the mid-day meal program.

**Clinical Pearl / High-Yield Fact**
To improve the nutritious value of the mid-day meal program, schools can incorporate a variety of locally available, nutrient-dense foods that are easy to prepare and consume.

**Correct Answer: D.**