Correct Answer - Option 2 :

±3
__Concept:__

The radius of the circle x^{2} + y^{2} + 2gx + 2fy + c = 0 is given by r^{2} = g^{2} + f^{2} - c.

__Calculation:__

Comparing the given equation x2 + y2 - 2px + 6y - 7 = 0 with the general equation of the circle we get:

g = -p, f = 3, c = -7

Using the relation r2 = g2 + f2 - c, we get:

⇒ 52 = (-p)2 + 32 - (-7)

⇒ 25 = p2 + 9 + 7

⇒ p^{2} = 9

⇒ p = ±3