Given equation of the parabola is 4y² + 2x - 20y + 17 = 0

⇒ 4y² - 20y + 17 = - 2x

⇒

⇒

⇒

Comparing with standard form of parabola (y - a)² = - 4b(x - c) we get,

⇒

We know that the that the length of the latus rectum is 4b.

∴The correct option is C