challenge: What were some of the roles that Shia clerics began to assume, as a result of Tusi's developments, which were previously permitted only to imams?
  
  A. Conducting exorcisms and faith healing
  B. Collecting and distributing religious taxes, and organizing Friday prayers
  C. Leading pilgrimages to Mecca and Medina
  D. Leading armies in battles against non-Muslims
  Answer: 