Answer:
D. a conflict between a character and himself or herself.
Step-by-step explanation:
An internal conflict in a literary work can be defined as a conflict between a character and himself or herself. This is usually as a result of contradicting (opposing) beliefs, psychological struggles, needs or desires being nurtured in the mind of a character.
Basically, writers of a literary work such as a story use internal conflict as a way of creating suspense and the development of a character.
In English literature, an internal conflict is also referred to as man vs self.
For example, John struggling between having to eat three heavy meals daily to stay strong or following the recommendation of the dietician to burn some calories.