Concept:This question tests the ability to identify grammatical or logical errors in a sentence with three underlined parts.
Explanation:The sentence discusses the relationship between failure and success.
"The stepping stone" in part (a) is used figuratively to mean a means of progress.
Part (b) uses "however" correctly to introduce a contrast, and "successive failures" is grammatically proper.
Part (c) repeats "successive" before "stepping stones" — this repetition is intentional and logically correct because it emphasizes that not every failure acts as a step toward success.
All three underlined parts are grammatically sound and convey the intended meaning without any error.
Therefore, the sentence as a whole is error-free.
Answer:(d)