Find the standard form of the equation of the circle with the given properties: Center at the origin, containing the point (-6,9), and tangent to the x-axis. Which of the following options represents the standard form of the equation?

Option A: (x² + y²) - 6x + 9y + 45 = 0
Option B: (x² + y²) - 6x + 9y - 45 = 0
Option C: (x² + y²) + 6x - 9y + 45 = 0
Option D: (x² + y²) + 6x - 9y - 45 = 0