Vector Algebra: JEE Main 2017 Mathematics question

Let $\overrightarrow a = 2\widehat i + \widehat j -2 \widehat k$ and $\overrightarrow b = \widehat i + \widehat j$. Let $\overrightarrow c$ be a vector such that $\left| {\overrightarrow c - \overrightarrow a } \right| = 3$, $\left| {\left( {\overrightarrow a \times \overrightarrow b } \right) \times \overrightarrow c } \right| = 3$ and the angle between $\overrightarrow c$ and $\overrightarrow a \times \overrightarrow b$ is $30^\circ$. Then $\overrightarrow a .\overrightarrow c$ is equal to :