The factors of x4 + x2 + 25 are:

Answer: Option B

x⁴ + x² + 25
Check by the option,
(x² - 3x + 5)(x² - 3x + 5)
= x⁴ - 3x³ + 5x² + 3x³ - 9x² + 15x + 5x² - 15x + 25
= x⁴ + x² + 25

Other Method
Let the value of x = 1
then, x⁴ + x² + 25 = 27
Now check options, and there is only one option that is equal to 27.
(1 + 3 + 5)(1 - 3 + 5) = 9 × 3 = 27