Which regular expression should be used to scan data for and remove characters other than text or numbers?

Which regular expression should be used to scan data for and remove characters other than text
or numbers?

A.
s/A-Za-z0-9]*//;

B.
s/^A-Za-z0-9]//g;

C.
s/^A-Za-z0-9]*//g;

D.
s/A-Za-z0-9]*//g;