<prompt>  The preferred treatment option for primary syphilis is :Injection Benzathine pencillin 2.4 million units IM single doseInjection Benzathine penicillin 2.4 million units IM Once a week for 3 weeksCap. Doxycycline 100 mg orally twice a day for 2 weeksTab. Azithromycin 2 gin single dose 