To multiply \(\sqrt{7}\) and \(-\sqrt{2}\), we can follow these steps:
\[ \sqrt{7} \cdot (-\sqrt{2}) = -(\sqrt{7} \cdot \sqrt{2}) \]
Using the property of square roots, we can combine the radicals:
\[ \sqrt{7} \cdot \sqrt{2} = \sqrt{7 \cdot 2} = \sqrt{14} \]
Thus, the multiplication becomes:
\[ -(\sqrt{14}) = -\sqrt{14} \]
So the exact answer is \(-\sqrt{14}\), which corresponds to option B:
B. - radical 14