We know that According to Algebra of Real Functions :
If f and g are two real functions which are defined under the same domain then (f + g)(x) = f(x) + g(x)
Given f(x) = x³ - 2x² + 1 and g(x) = 4x³ - 5x + 7
⇒ (f + g)(x) = f(x) + g(x)
⇒ (f + g)(x) = x³ - 2x² + 1 + 4x³ - 5x + 7
⇒ (f + g)(x) = 5x³ - 2x² - 5x + 8
Last Option is the Answer