Looks like MD to me. A giveaway is the doubling on the mint mark. Because mint marks were punched into the die after it was hubbed, the BIG 1969 S doubled die does not show doubling on the mint mark. On the other hand, I believe there have been machine doubled true doubled die versions of the 1969 S
DDO found as well. It may be confusing, but here's a resource to help you out:
http://coppercoins.com/ Just use the "die variety search" on the left hand side of the main page to search specific year and mint mark combinations.