The answer is B, i'm pretty sure
1. Infected needles
2. Insect bite
3. Organ transplant
4. Blood transfusion
In the ICD-10-CM index to diseases and injuries (alphabetic index), the code next to the main term called a default code. It would represent the condition that is commonly related with the main term. In a case where the condition is not documented in a record without any information, then this code should be assigned.