Four similar looking words are given. Choose the correctly spelt English word from the options provided.

Introduction / Context:
This spelling question focuses on a common but slightly tricky English word related to peace and calm. Examinations often test such words because they appear frequently in essays and comprehension passages. Knowing the standard spelling helps in writing polished English and understanding formal texts without confusion.

Given Data / Assumptions:

• The four options are: Tranquility, Tranquillity, Trankquility, and Trankwility.
• We must pick the spelling accepted in standard English usage.
• The word means calmness, peace, or a quiet state.

Concept / Approach:
There are two common variants for this word in English: “tranquillity” (with double “l”) is traditional British spelling, while “tranquility” (with single “l”) is often used in American English. Many Indian examinations follow British spelling conventions, which is why “tranquillity” with a double “l” is usually treated as correct. Also, the beginning part “tranquil” remains unchanged, and the suffix “lity” is attached, resulting in “tranquillity”. Options that change “tranq” to “trank” are clearly incorrect.

Step-by-Step Solution:
Step 1: Identify the root word “tranquil”, which is spelt t r a n q u i l. Step 2: Add the suffix “lity” to form the abstract noun, giving t r a n q u i l l i t y. Step 3: Compare this form with the given options. Option B, “Tranquillity”, matches the double “l” pattern and keeps the “tranquil” root intact. Step 4: Option A, “Tranquility”, uses a single “l”. This form appears in some American texts but is not normally preferred in British oriented exams. Step 5: Options C and D change “tranq” to “trank”, which does not match the correct root word and are incorrect spellings.

Verification / Alternative check:
Checking a British English dictionary or exam based word list will show “tranquillity” as the standard spelling. Some international dictionaries list both forms but usually mark the double “l” version as British. Since most competitive English questions in such exams follow British norms, the safe and expected choice is “Tranquillity”.

Why Other Options Are Wrong:
Option A: “Tranquility” is acceptable in American English but is often not treated as correct in exams that follow British spelling patterns. Option C: “Trankquility” has the wrong consonant cluster “trank”, which is not part of the real word. Option D: “Trankwility” has both the wrong initial cluster “trank” and the wrong internal spelling, so it is clearly incorrect.

Common Pitfalls:
Students sometimes forget whether the double consonant appears in the root or only in the derivative form. Remember that the root “tranquil” has one “l”, but when we form “tranquillity” another “l” is added due to the suffix, resulting in two “l” characters in a row. Also, never replace “qu” with “k” in such words, because “qu” is a stable letter combination in English that represents a particular sound.

Final Answer:
The correctly spelt word in the context of standard exam oriented English is Tranquillity.