Given the Following Sorites: Some K Are Not G

Given the following sorites: Some K are not G.
All N are G.
All F are N.
All T are F.
Some T are K.
This sorites is:

A) Invalid because a negative premise requires a negative conclusion.
B) Is invalid because one of the middle terms is undistributed.
C) Is invalid because a universal premise requires a universal conclusion.
D) Is valid because a particular premise requires a particular conclusion.
E) Is valid because no rules are broken.