Assertion (A) a, b, c, d are position vectors of 4 points such that \(2 \mathbf{a}-3 \mathbf{b}+7 \mathbf{c}-6 \mathbf{d}=0 \Rightarrow\) \(\mathbf{a}, \mathbf{b}, \mathbf{c}, \mathbf{d}\) are coplanar. Reason (R) Vector equation of the plane passing through three points whose position vectors are \(\mathbf{a}, \mathbf{b}, \mathbf{c}\) is \(\mathbf{r}=(1-x-y) \mathbf{a}+x \mathbf{b}+y \mathbf{c}\). Which of the following is true?

1. A Both \((A)\) and \((R)\) are true and \((R)\) is the correct explanation of (A)
2. B Both \((A)\) and (R) are true, but (R) is not the correct explanation of \((A)\)
3. C \((A)\) is true, but \((R)\) is false
4. D \((A)\) is false, but \((R)\) is true