Neapolitan Two Diamonds

A bid showing a hand with 17-24 HCP and 4441 or 4450 distribution. Responder bids

(a) 2S = 0-5 points and three or more spades. If opener's shortness is in spades, opener bids 2NT, then allows responder to place the contract in one of the other 3 suits.

(b) three of a suit = 5-6 HCP and a broken 6 card suit
(c) 2NT = responder has 6-7 HCP and a long suit with 2 of top three or three of top 5 honors. Opener then bids suit BELOW the shortness.
(d) 2H = hand that does not fit one of the previous three bids. Opener then rebids as follows

(i) 2NT = minimum hand and club shortness
(ii) 3C = minimum hands and diamonds shortness
(iii) 3H = maximum and club shortness
(iv) 3S = maximum and diamond shortness
(v) 2S = minimum and major suit singleton (responder bids 2NT to find shortness, and opener bid 3C with heart,
3D with spade shortness and 17-18 HCP, 3H with spade shortness and 19-20 HCP))