Question

If A + B # C - D, then A is D's _________.

• A. Sister
• B. Grandfather
• C. Grandmother
• D. Father
• A. A - B + C # D * E
• B. A * B # C * D - E
• C. A # B * C + D - E
• D. A + B - C * D # E

Answer 1

The Correct Option is C

Step 1: Decode the chain left to right.
$A + B$ $⇒$ $A$ is mother of $B$.
B # C $⇒$ $B$ is father of $C$.
$C - D$ $⇒$ $C$ is brother of $D$ (so $C$ and $D$ are children of the same parents).
Step 2: Relate $A$ to $C$ and $D$.
Since $A$ is mother of $B$ and $B$ is father of $C$, $A$ is grandmother of $C$. 
As $C$ and $D$ are siblings, $A$ is also grandmother of $D$. \[ \boxed{\text{A is D's grandmother}} \]

Answer 2

Goal: A must be female and the sister of a parent of E.

Check (A): A − B (A brother of B) ⇒ A is male. Not an aunt. Reject.

Check (B):
A * B (A sister of B) ⇒ A is female.
B # C (B father of C).
C * D (C sister of D) ⇒ C and D are siblings.
D − E (D brother of E) ⇒ D and E are siblings; hence C is also a sibling of E.
Therefore B (father of C) is also father of E (same parent set).
Since A is the sister of B and B is a parent of E, A is the aunt of E. Accept.

Check (C): A # B (A father of B) ⇒ A male (grandfather-type relation later), not aunt. Reject.

Check (D): A + B (A mother of B) and trailing links make A a grandparent of E, not aunt. Reject.

Answer: (B) makes A the aunt of E.