user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: name the medical trial that spotted fevers has been tested for.? 
Knowledge Triplets: Tick-borne rickettsioses, medicine.icd_9_cm_classification.includes_classifications, Ehrlichiosis
Tick-borne rickettsioses, medicine.icd_9_cm_classification.code, 082
m.0b717_x, organization.leadership.person, Nazi human experimentation
Tick-borne rickettsioses, medicine.icd_9_cm_classification.includes_classifications, Queensland tick typhus
Queensland tick typhus, medicine.icd_9_cm_classification.parent_classification, Tick-borne rickettsioses
Freezing, medicine.medical_treatment.trials, Nazi human experimentation
Nazi human experimentation, medicine.medical_trial.treatment_being_tested, Spotted fevers
North Asian tick fever, medicine.disease.parent_disease, Tick-borne rickettsioses
Nazi human experimentation, medicine.medical_trial.treatment_being_tested, Sea
Spotted fevers, medicine.disease.parent_disease, Tick-borne rickettsioses
Ehrlichiosis, medicine.disease.parent_disease, Tick-borne rickettsioses
Nazi human experimentation, user.avh.default_domain.ellerdale_topic.ellerdale_id, 00b0-514e
Queensland tick typhus, medicine.disease.parent_disease, Tick-borne rickettsioses
m.0qxf1mm, dataworld.gardening_hint.last_referenced_by, Nazi human experimentation
Tick-borne rickettsioses, medicine.disease.includes_diseases, Queensland tick typhus
Tick-borne rickettsioses, medicine.disease.includes_diseases, Boutonneuse fever
Sea, medicine.medical_treatment.trials, Nazi human experimentation
Spotted fevers, medicine.icd_9_cm_classification.parent_classification, Tick-borne rickettsioses
Nazi human experimentation, business.board_member.leader_of, m.0b717_x
Nazi human experimentation, medicine.medical_trial.treatment_being_tested, Sulfur mustard
Nazi human experimentation, medicine.medical_trial.treatment_being_tested, Sulfanilamide
Boutonneuse fever, medicine.disease.parent_disease, Tick-borne rickettsioses
Boutonneuse fever, medicine.icd_9_cm_classification.parent_classification, Tick-borne rickettsioses
Tick-borne rickettsioses, medicine.icd_9_cm_classification.includes_classifications, Tick-borne rickettsiosis, unspecified
Tick-borne rickettsioses, medicine.icd_9_cm_classification.includes_classifications, Boutonneuse fever
Nazi human experimentation, medicine.medical_trial.treatment_being_tested, Freezing
Spotted fevers, medicine.medical_treatment.trials, Nazi human experimentation
Tick-borne rickettsioses, medicine.icd_9_cm_classification.includes_classifications, Spotted fevers
Tick-borne rickettsioses, medicine.disease.includes_diseases, Ehrlichiosis
Tick-borne rickettsioses, medicine.icd_9_cm_classification.includes_classifications, Other specified tick-borne rickettsioses
Nazi human experimentation, base.schemastaging.context_name.pronunciation, g.11bt_5qr41
North Asian tick fever, medicine.icd_9_cm_classification.parent_classification, Tick-borne rickettsioses
Tick-borne rickettsioses, medicine.icd_9_cm_classification.includes_classifications, North Asian tick fever
Tick-borne rickettsioses, medicine.disease.includes_diseases, North Asian tick fever
Other specified tick-borne rickettsioses, medicine.icd_9_cm_classification.parent_classification, Tick-borne rickettsioses
Ehrlichiosis, medicine.icd_9_cm_classification.parent_classification, Tick-borne rickettsioses
Nazi human experimentation, medicine.medical_trial.treatment_being_tested, Poison
Poison, medicine.medical_treatment.trials, Nazi human experimentation
Sulfanilamide, medicine.medical_treatment.trials, Nazi human experimentation
Tick-borne rickettsiosis, unspecified, medicine.icd_9_cm_classification.parent_classification, Tick-borne rickettsioses
Sulfur mustard, medicine.medical_treatment.trials, Nazi human experimentation
Tick-borne rickettsioses, medicine.disease.includes_diseases, Spotted fevers
Spotted fevers, medicine.icd_9_cm_classification.code, 082$002E0

Answer: Nazi human experimentation