Correct option is A
Given:
T is the daughter of A.
A is married to M.
M is the son of K.
K is married to J.
J is the father of D.
D is the brother of N.
G is the son of N.

From the given information blood relation diagram will be.

K is Father's mother of T.
Note: here we don't know gender of N so K can be mother's mother also of G but Mother's mother is not given in options so Father's mother will be correct.
Thus, correct option is (a).