Consider the statement : "P(n) : n² – n + 41 is prime". Then which one of the following is true ?

If a circle C passing through the point (4, 0) touches the circle x² + y² + 4x – 6y = 12 externally at the point (1, – 1), then the radius of C is :

If the parabolas y² = 4b(x – c) and y² = 8ax have a common normal, then which on of the following is a valid choice for the ordered triad (a, b, c)?

The plane passing through the point (4, –1, 2) and parallel to the lines  $${{x + 2} \over 3} = {{y - 2} \over { - 1}} = {{z + 1} \over 2}$$  and  $${{x - 2} \over 1} = {{y - 3} \over 2} = {{z - 4} \over 3}$$ also passes through the point -