Spelling and vocabulary: choose the correctly spelt word to complete the sentence The threat of an epidemic caused great alarm and ____.

Introduction / Context:
This question tests both spelling and vocabulary. The sentence reads The threat of an epidemic caused great alarm and _____. We need a noun that matches alarm in meaning and is spelled correctly. The intended word is trepidation, which means fear, anxiety, or nervousness about what may happen in the future.

Given Data / Assumptions:

The sentence context is fear caused by a possible epidemic.
The missing word must be a noun that logically follows alarm and forms a natural pair with it.
Several similar looking spellings are provided, but only one reflects standard English.

Concept / Approach:
Trepidation is a standard English noun meaning fear or anxiety about something that may happen. It is often used in formal contexts such as with some trepidation or filled with trepidation. Spelling questions of this type usually offer the correct word alongside common misspellings that add or omit letters. Our task is to recognise the standard spelling trepidation and reject versions with extra letters or wrong vowel patterns.

Step-by-Step Solution:
Step 1: Note the sentence The threat of an epidemic caused great alarm and ____ and predict a word meaning fear or nervousness. Step 2: Recall that trepidation is a word that fits both in meaning and in register with alarm. Step 3: Examine option A Trepidation and confirm that this is the dictionary spelling: t r e p i d a t i o n. Step 4: Compare it with the other options and notice extra letters or incorrect vowel sequences in each of them. Step 5: Choose Trepidation as the correctly spelt word.

Verification / Alternative check:
We can verify the meaning by placing the word into similar sentences, for example She opened the letter with some trepidation. In all such uses, trepidation expresses a mix of fear and anxiety about an uncertain outcome, which perfectly matches the setting of an impending epidemic. A quick mental comparison with known English spelling patterns also supports trepidation as correct, since the suffix dation is common in words such as validation and degradation.

Why Other Options Are Wrong:
Option B Terpidation replaces e with e r in the first syllable, which does not match the standard spelling and is not recognised in dictionaries.
Option C Trepidition inserts an extra i, creating a nonstandard and incorrect ending dition instead of dation.
Option D Trepidattion doubles the t in the middle, again deviating from normal English spelling rules for this word.
Option E Treppidation introduces an extra p, which is not present in the correct form and makes the option invalid.

Common Pitfalls:
Spelling questions often use double letters and vowel changes to confuse candidates, especially in less common words. A good way to prepare is to study high frequency exam vocabulary lists and pay attention to patterns such as tion, sion, and dation endings. Remembering the meaning also helps; once you know that trepidation is a standard word meaning fear, you can focus on recalling its correct form instead of being misled by incorrect variants.

Final Answer:
The correctly spelt word that fits the context is Trepidation.