In the following question, out of the four alternatives, select the alternative which is the best one-word substitute for the expression "decrease or fade gradually before coming to an end".

Introduction / Context:
This question asks for a one-word substitute for the phrase "decrease or fade gradually before coming to an end." The idea is of something that does not stop suddenly but slowly dwindles until it finally disappears. English has a specific verb for this process, especially in the phrasal form "peter out." Recognising that verb is the key to answering correctly.

Given Data / Assumptions:

• Phrase to substitute: "Decrease or fade gradually before coming to an end."
• Options: Surge, Accrual, Peter, Swell.
• We assume the verb is used in the sense commonly found in the phrasal verb "peter out."
• The correct choice must describe a process of gradual decline, not increase.

Concept / Approach:
The English verb "peter" (almost always used as "peter out") means to diminish gradually and then stop, especially after starting strongly. For example, "The protests soon petered out," or "Their enthusiasm petered out after a few weeks." This meaning exactly matches the description in the question. In contrast, surge and swell describe increases, and accrual refers to gradual growth in amount, usually of money or interest, not fading away.

Step-by-Step Solution:
Step 1: Focus on the core idea: something gradually decreases or fades before finally ending. Step 2: Examine "Peter." As a verb in the expression "peter out," it means to dwindle or diminish slowly until nothing is left, matching the phrase perfectly. Step 3: Examine "Surge." This means to rise or increase suddenly and powerfully, which is the opposite of gradual fading. Step 4: Examine "Accrual." This noun refers to the process of gradual accumulation, usually in a positive or increasing sense, not decrease. Step 5: Examine "Swell." This verb means to grow larger or more intense, again describing increase rather than gradual decline. Step 6: Conclude that "Peter" (understood in the sense of "peter out") is the only option that aligns with the idea of gradually fading away.

Verification / Alternative check:
Consider example sentences: "The storm petered out before reaching the coast," or "Interest in the project petered out after the initial excitement." In these sentences, "petered out" clearly means that intensity or interest decreased slowly until it effectively ended. There is no equivalent usage like "the storm surged out" or "the storm swelled out" to mean decline. This confirms that "peter" is the correct verb for this gradual fading process.

Why Other Options Are Wrong:
"Surge" is wrong because it describes a sudden rise, such as a surge in demand or a surge of emotion. "Accrual" is wrong because it refers to accumulation or build up, the opposite of fading. "Swell" is wrong because it indicates expansion or growth in size or intensity. None of these words capture the idea of something slowly dwindling to nothing.

Common Pitfalls:
Some candidates may be unfamiliar with "peter" as a verb and think of it only as a proper name, which can lead them to avoid it. Others may pick "accrual" simply because it sounds technical or process-related, without noticing that it implies increase, not decrease. Developing a habit of reading broadly in English will expose you to verbs like "peter out" and help you recognise them in exam questions.

Final Answer:
The correct one-word substitute is Peter, as in "to peter out."