This question tests your understanding of third conditional sentences in English grammar. The third conditional is used to talk about hypothetical situations in the past and their imaginary results.

The structure of a third conditional sentence is:

$\mathrm{If}+\mathrm{past}\mathrm{perfect},\mathrm{would}+\mathrm{have}+\mathrm{past}\mathrm{participle}$

Step 1: Analyze the "if" clause.
The sentence begins with "If I hadn't eaten the hamburger". This is the if-clause and is correctly in the past perfect tense ("had not eaten"), which describes a condition that was not true in the past.

Step 2: Identify the correct result clause.
The result clause describes the consequence of that untrue condition. The consequence is that Sumit would not have fallen sick. The standard and most common structure for the result clause in a third conditional is "would + have + past participle".

Step 3: Evaluate the options.

• wouldn't have: This is the contraction of "would not have". It is the standard, correct form for the result clause in a third conditional sentence.
• may not have: "May" expresses possibility, not a certain result. It is less common and not the standard choice for this grammatical structure.
• couldn't have: "Couldn't have" expresses impossibility (e.g., "I couldn't have known that"). It does not fit the context of a simple hypothetical result.
• shouldn't have: "Shouldn't have" is used to express regret about a past action that was done (e.g., "I shouldn't have eaten so much"). It is not used for the result clause of a conditional statement.

Final Answer: The correct answer is "wouldn't have". The completed sentence is: "If I hadn't eaten the hamburger, I wouldn't have fallen sick."

Related Topic: Conditional Sentences

There are four main types of conditional sentences, each used for different situations:

• Zero Conditional: Used for general truths and facts. (Structure: If + present simple, ... present simple.)
• First Conditional: Used for real and possible future situations. (Structure: If + present simple, ... will + base verb.)
• Second Conditional: Used for unreal or improbable present/future situations. (Structure: If + past simple, ... would + base verb.)
• Third Conditional: Used for unreal past situations, as in this question. (Structure: If + past perfect, ... would have + past participle.)

Key Formulae (Structures)

Third Conditional Formula:

$\mathrm{If}\left[\mathrm{subject}\right]\mathrm{had}\mathrm{past}\mathrm{participle},\left[\mathrm{subject}\right]\mathrm{would}/\mathrm{could}/\mathrm{might}\mathrm{have}\mathrm{past}\mathrm{participle}$