Assertion : Kinetic energy of photo electrons emitted by a photosensitive surface depends upon the intensity of incident photon.
Reason : The ejection of electrons from metallic surface is possible with frequency of incident photon below the threshold frequency.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If assertion and reason both are false.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the kinetic energy of photoelectrons emitted from a photosensitive surface depends on the intensity of the incident photons.
- According to the photoelectric effect, the kinetic energy (K.E.) of emitted photoelectrons is given by the equation:
\[ K.E. = h\nu - \phi \]
where \(h\) is Planck's constant, \(\nu\) is the frequency of the incident photon, and \(\phi\) is the work function of the material.
- The assertion is incorrect because the kinetic energy of photoelectrons depends on the frequency of the incident photons, not the intensity. Intensity affects the number of emitted electrons but not their kinetic energy.

2. **Understanding the Reason**:
- The reason states that the ejection of electrons from a metallic surface is possible with the frequency of incident photons below the threshold frequency.
- This statement is also incorrect. For photoemission to occur, the frequency of the incident photons must be greater than or equal to the threshold frequency (\(\nu_0\)). If the frequency is below the threshold frequency, no electrons will be emitted, regardless of the intensity of the light.

3. **Conclusion**:
- Both the assertion and the reason are false. Therefore, the correct answer is that neither the assertion nor the reason is correct.

### Final Answer:
Both the assertion and the reason are false.