Answer:
Option D. It's a perfect square trinomial.
Explanation:
(a) 36x² - 4x + 16
= (6x)² - 2(2x) + (4)²
It's not a perfect square trinomial
(b) 16x² - 8x + 36
= (4x)² - 2x(4x) + (6)²
It's not a perfect square trinomial
(c) 25x² + 9x + 4
= (5x)² + 2
+ (2)²
It's not a perfect square trinomial
(d) 4x² + 20x + 25
= (2x)² + 2(10x) + (5)²
= (2x+5)²
It's a perfect square trinomial.