There are three options for me after 3c strong jumpshift: 3D, 3S and 4c. First of all, 4s is out of scope because this hand is too strong for this limited raise. I believe that 3S would be choice of the most players due to the apparent reason. 4c could be second choice. But 3D is my choice after analysis of the hand. There isn't very good support to partner in that two suits and diamond could be the hole for the 6 Spade, which I believe the likely final contract for most 3S bidders. The advantage of 3D is its flexiblity. It is a strong reponse and doesn't deny anything about S and C. It leaves more space and fore partner to further describe his hand. It also protect the weakest suit of the hand esp. when I am trying to play 6NT. I believe the 6NT would be the best contract if slam is possible.