Statement I: In calculating the disturbance produced by a pair of superimposed incoherent wave trians, you can add their intensities.
Statement II: `I_(1) + I_(2) + 2 sqrt(I_(1) I_(2)) cos delta`. The average value of `cos delta = 0` for incoherent waves.

Options

A. Statement I is True, statement II is True, Statement II is a correct explanation for Statement I.
B. Statement I is Ture, Statement II is Ture, Statement II is NOT a correct explanation for Statement I.
C. Statement I is True, Statement II is False.
D. Statement I is False, Statement II is True.

Explanation

To solve the given problem, we need to analyze both statements provided and determine their validity in the context of wave optics, specifically regarding incoherent waves.

### Step-by-Step Solution:

1. **Understanding Statement I**:
- Statement I claims that when calculating the disturbance produced by a pair of superimposed incoherent wave trains, their intensities can be added.
- Incoherent waves do not have a fixed phase relationship, which means they do not interfere constructively or destructively in a predictable manner.
- For incoherent waves, the resultant intensity \( I \) is simply the sum of the individual intensities \( I_1 \) and \( I_2 \).
- Therefore, this statement is **true**.

2. **Understanding Statement II**:
- Statement II provides the formula for the resultant intensity of two superimposed waves:
\[ I = I_1 + I_2 + 2 \sqrt{I_1 I_2} \cos \delta \]
- Here, \( \delta \) represents the phase difference between the two waves.
- For incoherent waves, the average value of \( \cos \delta \) is 0 because the phase difference varies randomly.
- Thus, when averaging over time or many cycles, the term \( 2 \sqrt{I_1 I_2} \cos \delta \) contributes nothing to the average intensity, leading to:
\[ I = I_1 + I_2 \]
- Therefore, this statement is also **true**.

3. **Conclusion**:
- Since both statements are true, and Statement II explains why Statement I is true, we conclude that:
- Statement I is true.
- Statement II is true.
- Statement II is the correct explanation for Statement I.

### Final Answer:
Both statements are true, and Statement II is the correct explanation for Statement I.