{HEAD ~ The challenge question} presented can be selected based on an analysis of the risk of {TAIL ~ the transaction} and potentially other factors  
{ HEAD ~ The challenge question } presented can be selected based on an analysis of the risk of { TAIL ~ the transaction } and potentially other factors
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH