The energy ($E$) of a photon is related to its wavelength ($\lambda$) by the Planck's equation: $E = \frac{hc}{\lambda}$.

1. Identify Given Values: Planck's constant ($h$) = $6.63 \times 10^{-34} \text{ Js}$ Speed of light ($c$) = $3 \times 10^8 \text{ ms}^{-1}$

• Wavelength ($\lambda$) = $45 \text{ nm} = 45 \times 10^{-9} \text{ m}$

2. Calculation: $E = \frac{(6.63 \times 10^{-34}) \times (3 \times 10^8)}{45 \times 10^{-9}}$ $E = \frac{19.89 \times 10^{-26}}{45 \times 10^{-9}}$ $E = 0.442 \times 10^{-17} \text{ J}$ $E = 4.42 \times 10^{-18} \text{ J}$

Thus, the energy corresponds to Option D.