(N/A) The primary theories explaining the propagation of light are:
$1$. $Corpuscular$ $Theory$: Proposed by $Isaac$ $Newton$,it suggests that light consists of tiny particles called corpuscles.
$2$. $Wave$ $Theory$: Proposed by $Christiaan$ $Huygens$,it suggests that light travels in the form of waves through a hypothetical medium called $luminiferous$ $ether$.
$3$. $Electromagnetic$ $Wave$ $Theory$: Proposed by $James$ $Clerk$ $Maxwell$,it states that light consists of oscillating electric and magnetic fields propagating through space.
$4$. $Quantum$ $Theory$ ($Photon$ $Theory$): Proposed by $Max$ $Planck$ and $Albert$ $Einstein$,it explains that light consists of discrete packets of energy called $photons$.