Properties of a parallelogram:<br><br>
&bull; Opposite sides are parallel: AD \( \parallel \) BC and AB \( \parallel \) DC. (Statements A and B are TRUE.)<br>
&bull; Opposite angles are equal: \( \angle \)a = \( \angle \)c. (Statement C is TRUE.)<br>
&bull; Adjacent angles are NOT necessarily equal; they are supplementary (sum to 180&deg;).<br>
&bull; \( \angle \)a = \( \angle \)b is NOT always true in a parallelogram (only true for a rectangle).<br><br>
Final Answer: \( \angle a \) is equal to \( \angle b \)