Let \( \vec{a}=-\hat{i}-\hat{j}+\hat{k} \), \( \vec{a}\cdot\vec{b}=1 \) and \( \vec{a}\times\vec{b}=\hat{i}-\hat{j} \). Then \( \vec{a}-6\vec{b} \) is equal to:
\( 3(\hat{i}-\hat{j}+\hat{k}) \)
\( 3(\hat{i}-\hat{j}-\hat{k}) \)
\( 3(\hat{i}+\hat{j}+\hat{k}) \)
\( 3(\hat{i}+\hat{j}-\hat{k}) \)