Final answer:
Christina's situation is known as 'progression', which is the stage in disease pathology where symptoms become more severe and specific after the initiation phase.
Step-by-step explanation:
Based on the provided information, Christina's situation seems to relate to the stages of a disease, particularly in the context of the progression of medical conditions. When reviewing the answer choices provided in relationship to disease pathology, the term 'progression' is the correct answer. It refers to the stage of a disease during which symptoms become more severe and specific, following an initial period of general symptoms. This is typically observed after the 'initiation' phase, where the disease starts or 'initiates' in the body. It's worth noting that the concept of 'promotion' might apply to other contexts but not explicitly to disease pathology.