Final answer:
The symptoms described in the question are consistent with leukemia, a type of cancer that affects the blood cells.
Step-by-step explanation:
The symptoms described in the question are fever, anorexia, fatigue, weight loss, pallor, cervical adenopathy, splenomegaly, skin ecchymoses, and petechiae.
These symptoms are characteristic of leukemia, which is a type of cancer that affects the blood cells. Leukemia can cause abnormal production of blood cells, leading to fatigue, increased susceptibility to infections, and abnormal bleeding.
In the given scenario, the most likely diagnosis would be A) Leukemia. It is important for the child to receive proper medical evaluation and treatment for their condition.