Carbocations in chemistry is known as the carbon atoms that are positive and are ions. Hence, the name is similar to the description of carbocations. These are believed to be alkanes and can donate to H+. It may seem unusual because most alkanes are known for being lazy, so to speak, these are more active.
This atom has six electrons. These are located in the outer part of the atom. It contradicts the octet rule that this type is known for because the octet rule has eight electrons. The atom is expected to increase in stability and it would best be known based on the diagram of each part of the carbocation process.
In this case, the rank of these diagrams would be with diagram A first, diagram B would be second and diagram D would be third.
There is a positive charge in D adjacent to a double bond. This results in resonance stabilization of the molecule, making it more stable than A and B. Between A and B, A is a primary carbocation, and B is a secondary carbocation, and tertiary carbocations > secondary > primary carbocations in terms of stability.