Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: MoscowAnna Alimova works on the front lines of Russia's growing HIV epidemic. On a Friday night, the mother of two with a shock of bright pink hair stands outside a 24-hour pharmacy in a leafy Moscow neighborhood. She cheerfully offers plastic bags full of clean syringes to Russians dashing into and out of the store. "Mostly drug users have hepatitis," she says. "And many of them have HIV." According to the United Nations' UNAIDS program, Russia had the third-highest number of new HIV infections globally in 2015, behind South Africa and Nigeria. Russian government statistics show that more than half of new infections are transmitted through intravenous drug use. And the rate of infection is rising.Russia has the third-highest number of new HIV infections in the worldA federal center reported 1.1 million diagnosed cases of HIV in Russia 
 Question:Some _ drug abusers inject tropicamide, which doctors normally use to dilate pupils, into their veins to amplify the effects of other substances.

Russia