My deck+hand consists of the following, and nothing else:
A Duchies
B Dukes
C Gardens
D Silk Roads
E Estates
F Coppers
Assume (A+B+C+D+E+F) is a multiple of 10 and (A+B+C+D+E) is a multiple of 4 for easy Gardens/Silk Road math.
Gaining 1 of which card -- Duchy, Duke, Gardens, Silk Road, Estate, or Copper -- would give you the most +VP (assume there is at least 1 of that card left for you to gain)?
No shennanigans are in play (Possession, gaining 10 curses from Embargo tokens, etc.) -- just plain, old-fashioned card gaining.
Answer would be in terms of A, B, C, D, E, and F.
Bonus: come up with a similar puzzle that involves Vineyards, action cards, Feodums, silvers, etc.