1. $\boldsymbol{(A\cdot B)\cdot C}$ is undefined as $\boldsymbol{A\cdot B}$ is a scalar and we cannot take the inner product of a scalar with the vector $\boldsymbol{C}$.

2. $\boldsymbol{(A\cdot B)C}$ is a vector and is a multiple of $\boldsymbol{C}$ as $\boldsymbol{A \cdot B}$ is a scalar.

3. $\boldsymbol{(A\cdot B)\times C}$ is undefined as $\boldsymbol{A\cdot B}$ is a scalar and the cross product is only defined between vectors.

4. $\boldsymbol{(A\times B)\times C}$ is a vector as $\boldsymbol{A \times B}$ and $\boldsymbol{C}$ are vectors and the cross product between vectors produces a vector.

5. $\boldsymbol{(A\times B)\cdot C}$ is a scalar as $\boldsymbol{A \times B}$ and $\boldsymbol{C}$ are vectors and the inner or dot product is between vectors and produces a scalar.