In the following passage, some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives. And then, a few glorious minutes ______________, it was time to reluctantly head ashore. ____________ time, the strokes were more fluid, the movements more relaxed. I turned back one last time ____________ hello to a clown fish, the reason why I came to the Andamans. As I watched, it played hide-and-seek _________ a sea anemone, before frisking away. Suddenly, I realised a kinship with the blue waters ___________ the Bay of Bengal. I turned back one last time ____________ hello to a clown fish, the reason.

Introduction / Context:
This blank also belongs to the descriptive passage of a sea experience in the Andamans. The sentence I turned back one last time ____________ hello to a clown fish describes the action of the narrator turning and greeting the fish. The gap must be filled with a form that fits naturally between the verb turned back and the noun hello, forming a phrase of purpose similar to turned back one last time to say hello. The question tests knowledge of infinitive of purpose versus other verb forms.

Given Data / Assumptions:

• Target fragment: I turned back one last time ____________ hello to a clown fish.
• Options: to say, said, saying, says.
• The narrative is in simple past tense (turned back), describing a deliberate action with a purpose.
• We assume standard usage for expressing purpose with verbs of motion.

Concept / Approach:
In English, when we want to state the purpose of a movement or action, we often use the infinitive form to plus base verb. Common examples include I went to the shop to buy milk, She called to say thank you, and He turned around to wave. Here, the narrator turned back in order to say hello, so the correct structure is to say hello. The other verb forms either clash with the tense or do not express purpose in a natural way. Therefore, the approach is to recognise this as a purpose construction and select the plain infinitive to say.

Step-by-Step Solution:
Step 1: Identify the main verb in the clause: turned back, which is in the simple past tense.Step 2: Note that the action of turning back has a clear purpose: greeting the clown fish.Step 3: Remember that English normally expresses such purposes with to plus base verb: turned back to say hello.Step 4: Test each option in the sentence: turned back one last time to say hello, turned back one last time said hello, turned back one last time saying hello, turned back one last time says hello.Step 5: Only to say produces a smooth, grammatical phrase that expresses purpose. The other forms sound awkward or ungrammatical in this context.

Verification / Alternative check:
To verify, compare with similar narrative sentences: She looked back once more to wave goodbye, He returned to thank the guide, or They paused to take a photograph. All of these examples use the infinitive to state the reason for a previous action. Using said would require a different structure such as I turned back one last time and said hello, which is not what the blank format demands. Saying could work in a reduced non finite clause like I turned back, saying hello, but that changes the nuance and is less natural than the intended pattern in the test passage. Says is present tense and does not match the narrative past.

Why Other Options Are Wrong:
Said: The phrase turned back one last time said hello lacks a conjunction such as and and reads as if said hello were a separate clause awkwardly attached to turned back. Saying: Turned back one last time saying hello is grammatically possible but not the best fit here; it does not emphasise purpose clearly and is less idiomatic than to say. Says: This verb is in the simple present tense, which conflicts with the past tense narration and makes the sentence inconsistent in time.

Common Pitfalls:
Some candidates may see said and quickly associate it with hello, remembering the common phrase said hello, without noticing the missing conjunction or the required purpose structure. Others might choose saying because they know that a present participle can sometimes follow a main verb, but they forget that here the writer is expressing intention rather than simply describing two simultaneous actions. A reliable strategy is to ask what the reason for turning back was and then express that reason with to plus the appropriate verb, which naturally leads to to say.

Final Answer:
The correct word to complete the sentence is to say, giving I turned back one last time to say hello to a clown fish.