at (Single Correct)
I et \( a, b \), c be three distinct real numbers, none equal to one. If the vectors \( a \hat{i}+\hat{j}+\hat{k}, \hat{i}+b \hat{j}+\hat{k} \) and \( \hat{i}+\hat{j}+c \hat{k} \) are coplanar, then \( \frac{1}{1}+\frac{1}{16}+\frac{1}{1} \) is equal to
