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: (CNN) Sen. Mark Warner says the "million-dollar question" still unanswered about the Facebook election ads sold to Russian-linked accounts was how the Russians knew whom to target on Facebook. Warner, the top Democrat on the Senate intelligence panel, told CNN the committee expects this week to begin viewing the 3,000 Russian-linked Facebook ads, which Facebook earlier this month disclosed were connected to more than 450 inauthentic accounts. Facebook agreed last week to turn the ads over to the House and Senate intelligence committees. Warner's burning question involves not just the content of the ads but how they were deployed. "Did they know this just by following political news in America? Did they geo-target both geography and by demographics in ways that at least at first blush appear pretty sophisticated? These are the kind of questions that we need to get answered and that's why we need them in a public hearing," Warner said.The Senate intelligence committee has met with Facebook officials in a closed sessionTwitter officials are coming to talk to the panel Thursday in a closed session 
 Question:"A lot of the same claims that have been made about Facebook, have also been made about Twitter," Warner said, adding that it was "too early" to tell if they would be cooperative with congressional efforts to determine the scope of _ attempts to use social media in the 2016 election.

Russian