A small child falls down and cuts his knee. A few days later a scab forms over the wound. After a few weeks, the wound does not appear to be healing, but it is not infected. Which of the following could explain this?
A) The child has a platelet deficiency. B) The child has a mast cell deficiency. C) The child has a cytokine deficiency. D) The child has a neutrophile deficiency. E) Answers C or D are possible.