If \( \vec{a}=\hat{i}+2\hat{k},\,\vec{b}=\hat{i}+\hat{j}+\hat{k},\,\vec{c}=7\hat{i}-3\hat{j}+4\hat{k},\,\vec{r}\times\vec{b}+\vec{b}\times\vec{c}=\vec{0} \) and \( \vec{r}\cdot\vec{a}=0 \). Then \( \vec{r}\cdot\vec{c} \) is equal to:
\( 34 \)
\( 36 \)
\( 30 \)
\( 32 \)