If \( A \) is brother of \( B, C \) is brother of \( B \) , and \( A \) is brother of \( D \) , then which of the following must be true?
Step-by-step Solution:
$$ \begin{array}{c} \text{Parents} \\ \downarrow \\ \hline \begin{array}{cccc} \text{A (Brother)} & \text{B (Sibling)} & \text{C (Brother)} & \text{D (Sibling)} \end{array} \end{array} $$