In a rhombus, opposite angles are equal and consecutive angles are supplementary. Given that \( m\angle A = 114^\circ \), we can find \( m\angle B \).
Since the angles in a rhombus are supplementary, we have:
\[ m\angle A + m\angle B = 180^\circ \]
Substituting the known value:
\[ 114^\circ + m\angle B = 180^\circ \]
Now, solving for \( m\angle B \):
\[ m\angle B = 180^\circ - 114^\circ = 66^\circ \]
Thus, \( m\angle B \) is \( 66^\circ \).
The correct answer is 66°.