In the following one word substitution question, choose the alternative that best replaces the phrase "a person’s last performance", that is, the final work, appearance, or act of an artist, performer, or writer.

Introduction / Context:
This question examines your knowledge of one word substitutions that describe specific moments or stages in a person s creative or professional life. The phrase "a person s last performance" is often used for artists, singers, actors, or writers and refers to the final act or work they present before retiring or dying. English uses a poetic expression borrowed from an old legend about swans to capture this idea in a single term.

Given Data / Assumptions:

• The phrase to be replaced is "a person s last performance".
• Four different literary or technical terms are given as options.
• Only one expression literally refers to a final performance or act.
• You must match the phrase with the correct fixed expression used in English.

Concept / Approach:
The correct expression is "swan song". According to an old legend, swans are silent throughout their lives but sing beautifully just before they die. Thus, a "swan song" came to symbolise a person s last or farewell performance or work. The other options have different meanings: "prognosis" is a medical prediction, "elegy" is a poem of mourning, and "memoir" is a written record of personal experiences. Therefore, only "swan song" fits the phrase provided in the question.

Step-by-Step Solution:
Step 1: Focus on the key idea in the phrase: the final or last performance of a person. Step 2: Recall any idiomatic expressions or literary terms in English that refer to a last performance. Step 3: Remember the legend that a swan sings its most beautiful song just before death, giving us the term "swan song". Step 4: Compare this with the options and locate "Swan song". Step 5: Verify that the other options do not indicate a final performance but refer to entirely different concepts.

Verification / Alternative check:
Use the term in a sample sentence: "The famous actor s swan song was a deeply emotional film released shortly before his retirement." If we replace "swan song" with "last performance", the meaning remains unchanged, confirming the equivalence. However, if we substitute it with "elegy", "memoir", or "prognosis", the sentence becomes meaningless or stylistically wrong. This confirms that Option D is the correct one word substitution.

Why Other Options Are Wrong:

• Option A, "Prognosis", is a medical term for a doctor s forecast of the likely course of a disease.
• Option B, "Elegy", is a poem written to mourn the dead, not the final performance itself.
• Option C, "Memoir", is a written account of someone s own life or experiences, usually in book form.

Common Pitfalls:
Students sometimes confuse "elegy" with any kind of last work because it is associated with death or mourning, but it describes a poem about someone, not their final performance. Others may be unfamiliar with the legend behind "swan song" and may therefore ignore this term. To avoid such confusion, it is useful to study common literary terms and their origins, as these often appear in competitive exams and advanced English sections.

Final Answer:
The correct one word substitution for "a person s last performance" is Swan song, making Option D the right answer.