This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
Variola is a type of which pox virus? 
Select and explain. 
A. Parapoxvirus, B. Orthopoxvirus, C. Yatapox virus, D. Molluscipox virus
B: Orthopoxvirus
Answer: B: Orthopoxvirus 
Explanation: ANSWER: (B) Orthopox virusREF: Jawetz 24th ed chapter 34 table 34-2 POXVIRUSES CAUSING DISEASE IN HUMANSGenusVirusPrimary hostDiseaseOrthopoxvirusVariolaHumansSmallpox (now eliminated) VacciniaHumansLocalized lesion; used for smallpox vaccination BuffalopoxWater buffaloHuman infections rare; localized lesion MonkeypoxRodents, monkeyHuman infections rare; generalized disease CowpoxCowHuman infections rare; localized ulcerating lesionParapoxvirusOrfSheepHuman infections rare; localized lesionPseudocowpoxCowsBovine papular stomatitisCowsM olluscipoxvirusMolluscumcontagiosumHumansMany benign skin nodulesYatapoxvirusTanapoxMonkeysHuman infections rare; localized lesion YabapoxMonkeysHuman infections very rare and accidental; localized skin tumors