Improve the bracketed part of the sentence by choosing the correct option. If no improvement is required, select "No improvement". Sentence: Bull markets, John Templeton said, are born on pessimism, grow on scepticism, mature on optimism and (die for) euphoria.

Introduction / Context:
This sentence improvement question tests familiarity with a famous quotation about market cycles and also checks preposition choice. The quote describes how bull markets progress from pessimism to scepticism to optimism and finally to euphoria. The bracketed phrase die for euphoria is not the standard form of the quote and is not idiomatic English. You must pick the preposition that correctly completes the expression.

Given Data / Assumptions:

• The sentence is: Bull markets, John Templeton said, are born on pessimism, grow on scepticism, mature on optimism and die for euphoria.
• The bracketed part is die for.
• Options: die on, die at, die above, No improvement.
• We assume the sentence intends to reproduce the well known pattern born on, grow on, mature on, die on.

Concept / Approach:
In the original and widely quoted version, the phrase is die on euphoria. The preposition on is used consistently throughout: born on pessimism, grow on scepticism, mature on optimism and die on euphoria. Using for changes the meaning, suggesting that markets die for the sake of euphoria, which is not intended. At and above do not fit the established idiom and disrupt the parallel structure. Therefore, die on is the correct improvement.

Step-by-Step Solution:
Step 1: Observe the pattern in the earlier parts of the sentence: born on, grow on, mature on.Step 2: Recognise that to maintain parallel structure, the same preposition on should follow die as well.Step 3: Replace die for with die on and read the full sequence: born on pessimism, grow on scepticism, mature on optimism and die on euphoria, which now sounds balanced and idiomatic.Step 4: Consider die at and die above and see that they break the established pattern and do not match the metaphor.Step 5: Conclude that die on is the only option that both preserves the quote and maintains correct prepositional parallelism.

Verification / Alternative check:
Parallel structure is a strong cue in sentence correction. When three phrases use on, and the fourth suddenly uses for, it is very likely that the fourth is incorrect. Moreover, financial writers and exam preparation materials typically quote this aphorism with on in all four parts. Substituting die on for die for restores that well known form, confirming that die on is correct.

Why Other Options Are Wrong:
Die for suggests purpose or cause, as in soldiers die for their country, which is not what the metaphor intends. Die at and die above do not appear in any standard version of the quotation and do not convey the sense of a market cycle ending in a particular emotional state. No improvement is also wrong because it would keep a non standard and stylistically jarring preposition.

Common Pitfalls:
Test takers sometimes focus only on individual phrases and ignore patterns across a sentence. This question is designed to reward those who notice that on appears three times already and that a different preposition breaks symmetry without any clear reason. When you see repeated structures, it is usually safe to suspect that any break in the pattern is an error unless there is a strong contextual justification.

Final Answer:
The bracketed phrase die for should be corrected to die on to match the standard quotation and maintain parallel structure, so option A is correct.