In the following English sentence, identify the part that contains an error, or choose No error if the sentence is correct: He lost heart because he could not cope with the difficulties in life.

Introduction / Context:
This question focuses on the correct use of English phrasal verbs. Many learners confuse combinations such as cope up with and cope with. Examiners often test this by inserting a wrong preposition or an extra particle in an otherwise correct sentence.

Given Data / Assumptions:
- Sentence: He lost heart because he could not cope up with the difficulties in life. - Part A: He lost heart. - Part B: because he could not cope up with. - Part C: the difficulties in life. - Part D: No error.

Concept / Approach:
The correct idiomatic expression in standard English is cope with something, meaning to manage, handle, or deal successfully with a difficult situation. The phrase cope up with is non standard and considered incorrect in formal writing. Therefore, the error lies in the extra particle up, which should not be present.

Step-by-Step Solution:
Step 1: Identify the main phrasal verb: cope up with. Step 2: Recall the correct standard form: cope with. Step 3: Observe that the word up is unnecessary and ungrammatical in this context. Step 4: Replace cope up with by cope with to form a correct expression. Step 5: The rest of the sentence, He lost heart and the difficulties in life, is grammatically and idiomatically correct. Step 6: Therefore, the error occurs in Part B.

Verification / Alternative check:
Check standard usage: We say cope with pressure, cope with stress, cope with exams, and cope with loss. In each case, the pattern is cope with plus noun. Native speaker usage and grammar references do not list cope up with as correct. Replacing the phrase in the sentence gives He lost heart because he could not cope with the difficulties in life, which sounds natural and correct.

Why Other Options Are Wrong:
Part A He lost heart is a standard idiom meaning he became discouraged or lost courage. Part C the difficulties in life is grammatically correct and expresses the object of the verb cope with. Part D No error is not correct because there is clearly an error with the phrasal verb in Part B.

Common Pitfalls:
A very common pitfall for learners is to add up to many phrasal verbs, influenced by expressions like give up or pick up. However, not every verb plus preposition can be extended in this way. Another error is to ignore small preposition changes, even though they often decide whether an expression is standard. Always memorise common phrasal verbs exactly as they are used in reliable sources.

Final Answer:
The error is in Part B; the correct phrase is could not cope with.