Bohr's atomic theory gave the idea of :

Options

A. Nucleus
B. Shape of sub-levels
C. Quantum numbers
D. Stationary states .

Explanation

To solve the question regarding Bohr's atomic theory, we need to analyze the options provided and understand the key concepts introduced by Niels Bohr in 1913.

### Step-by-Step Solution:

1. **Understanding Bohr's Atomic Theory**:
- Niels Bohr proposed a model for the hydrogen atom based on quantum theory. His theory was revolutionary as it introduced the concept of quantized energy levels for electrons.

2. **Key Postulates of Bohr's Theory**:
- **Electrons revolve around the nucleus**: Bohr stated that electrons move in fixed paths or orbits around the nucleus.
- **Stationary Orbits**: These orbits are termed "stationary orbits" because electrons do not radiate energy while in these orbits.
- **Quantized Energy Levels**: Each orbit corresponds to a specific energy level, and electrons can only occupy these defined energy levels.
- **Quantum Numbers**: The energy levels are denoted by integers (n = 1, 2, 3, ...), which are known as quantum numbers.

3. **Analyzing the Options**:
- **Nucleus**: While Bohr's model involves the nucleus, it does not specifically give the idea of the nucleus itself.
- **Shape of Subshells**: Bohr's theory does not address the shapes of subshells; this concept comes from later quantum mechanical models.
- **Quantum Numbers**: Bohr introduced the idea of quantized energy levels, which are represented by quantum numbers. This is a correct statement.
- **Stationary States**: The term "stationary states" refers to the stable orbits where electrons do not radiate energy. This is also a correct statement.

4. **Conclusion**:
- The correct answers related to Bohr's atomic theory are **quantum numbers** and **stationary states**. However, since the question asks for the idea that Bohr's theory specifically gave, the best answer is **quantum numbers**.

### Final Answer:
The correct answer is **quantum numbers**.