Solve this:

$$\begin{gathered} \mathit{Q}\mathit{u}\mathit{e}\mathit{s}\mathit{t}\mathit{i}\mathit{o}\mathit{n}\mathbf{ }\mathit{N}\mathit{o}\mathbf{.}\mathbf{ }\mathbf{5}\mathbf{ } \\ If (A \cap B\text{'}) \cup B = A, (A \cap C\text{'}) \cup C = A and A \cap B = A \cap C, then which of the following relations is true? \\ A. A = B \\ B. B = C \\ C. C = A \\ D. None of these \end{gathered}$$