Step 1: Formula
\[ \vec{v} = \vec{\omega} \times \vec{r} \]
Step 2: Cross Product Calculation
\[ \vec{v} = \begin{vmatrix} \hat{i} & \hat{j} & \hat{k} \\ 3 & -4 & 1 \\ 5 & -6 & 6 \end{vmatrix} \]
\[ \vec{v} = \hat{i}(-24 - (-6)) - \hat{j}(18 - 5) + \hat{k}(-18 - (-20)) \]
Step 3: Simplifying
\[ \vec{v} = -18\hat{i} - 13\hat{j} + 2\hat{k} \]
Step 4: Conclusion
The linear velocity vector is \( -18\hat{i} - 13\hat{j} + 2\hat{k} \).
Final Answer: (C)