A. The energy of a photon is $E = h v$.

This statement is correct. The energy of a photon is given by the equation:

$E = h v$

where $E$ is the energy, $h$ is Planck's constant, and $v$ (also written as $\nu$) is the frequency of the photon.

B. The velocity of a photon is $c$.

This statement is also correct. In free space (vacuum), the velocity of light, and hence the velocity of a photon, is constant and is denoted by $c$.

C. The momentum of a photon, $p = \frac{h v}{c}$.

This statement is correct as well. The momentum $p$ of a photon can be expressed as:

$$p = \frac{E}{c} = \frac{h v}{c}$$

D. In a photon-electron collision, both total energy and total momentum are conserved.

This statement is correct. During collisions involving photons and electrons, such as Compton scattering, both energy and momentum are conserved.

E. Photon possesses positive charge.

This statement is incorrect. Photons are electrically neutral particles and do not possess any charge.

Based on the analysis, the correct statements are A, B, C, and D. Therefore, the correct answer is:

Option B
A, B, C, and D only