Which of the following activities can be compared to the concept of quantisation?

Calculate the energy in joule corresponding to light of wavelength $45 \ nm$. (Planck's constant,$h = 6.63 \times 10^{-34} \ J \ s$,speed of light,$c = 3 \times 10^8 \ m \ s^{-1}$)

The ratio of the difference in energy between the first and second Bohr orbits to that between the second and third orbits is

If the frequency of radiation emitted for the electron transition from an excited state to ground state of hydrogen atom is $\frac{3 X}{4} \ Hz$,the frequency of radiation absorbed for the electron transition from the above excited state to the next immediate excited state in $Hz$ is:

The energy required for the ionization of an excited hydrogen atom would be (in $eV$)-

How many spectral lines are obtained when an electron transitions from the $8^{th}$ orbit to the $1^{st}$ orbit in a hydrogen atom?