6. If the line $a x+b y=1$ intersects the circle $x^{2}+y^{2}=1$, then the position of point $P(a, b)$ is
A. on the circle
B. outside the circle
C. inside the circle
D. any of the above is possible
6. B Hint: From the given, $\frac{1}{\sqrt{a^{2}+b^{2}}}1$, so $P(a, b)$ is outside the circle $x^{2}+y^{2}=1$.