Pair of Tangents from a Point

Q. If O is the origin and OP, OQ are the tangents from the origin to the circle $x^2+y^2-6x+4y+8=0$, the circumcenter of the triangle OPQ is

1. 
2. 
3. 
4. 

Q.

The length of the intercept made by the normal at (1, 6) of the circle $x^2+y^2-4x-6y+3$ = 0 between the Coordinate axis is

1. $\sqrt{5}$

2. $\sqrt{5}$

3. $3\sqrt{10}$

4. $\sqrt{\frac{5}{2}}$

Q. An infinite number of tangents can be drawn from $(1,2)$ to the circle $x^2+y^2-2x-4y+\lambda =0.$ Then $\lambda$ is

1. $-20$
2. $20$
3. Not possible
4. $5$