I haven't done it for years.It's been years-----I did it.
a.since
b.for
c.from
d.as

• since
  coz for many years time duration since is used
• 8 years agoHelpfull: Yes(1) No(0)
• Since
  because the time it not fixed(years) so since should be used
  
• 8 years agoHelpfull: Yes(0) No(0)
• A. Since
  This is the only suitable answer
• 8 years agoHelpfull: Yes(0) No(0)