X - Z means X is the mother of Z ;
X x Z means X is the father of Z and
X + Z means X is the daughter of Z.
Now, if M - N x T + Q, than which of the following is not true ?
Answer: D. Q is wife of N
M - N x T + Q means M is the mother of N who is the father of T who is the daughter of Q i.e. M is the grandmother of the daughter of Q i.e. M is the mother of Q. Since this is not given in the choices, so the fact in (d) derived from N x T + Q is true.