B. Arguments is an array that contains every passed argument, regardless of whether it is enumerated explicitly.
A2:
A. You must use the VAR keyword to create a variable local to the UDF. Omitting VAR causes the variable to be created in the calling code's scope.
A3:
B and D. A is incorrect, as there is no difference in execution speed. C and E are incorrect, as the statements are true of both tag- and <cfscript>-based UDFs.