In the following question, four words are given, out of which only one word is correctly spelt. Select the correctly spelt English word.

Introduction / Context:
This spelling question tests your ability to recognise the correct standard English spelling among several similar looking options. The target word is declination, a noun used in contexts such as astronomy and general English to indicate a bending down, a slope, or a polite refusal. Correct spelling is essential in formal writing, academic work, and competitive exams, and questions like this help identify how well you know common prefixes, roots, and suffixes.

Given Data / Assumptions:

• Options: daclination, declineation, declination, daclineation.• Only one option matches the correct dictionary spelling.• We assume familiarity with related words like decline and inclination.• The correct form should follow normal English word formation rules.

Concept / Approach:
The word declination is formed from the root decline plus the suffix ation. When a verb ends in e, that e is usually dropped before adding the noun forming suffix ation, as in combine to combination and donate to donation. Thus, decline becomes declination. The incorrect alternatives introduce extra letters, wrong vowel patterns, or misordered consonants that do not follow typical English patterns and are not found in standard dictionaries.

Step-by-Step Solution:
Step 1: Recognise the base word decline, which you likely know.Step 2: Recall that the noun from decline is declination, following the pattern verb plus ation.Step 3: Examine option C declination. It matches the expected pattern exactly and looks familiar from usage in geography and astronomy.Step 4: Check option B declineation. This form doubles the vowel sequence e e and is not a standard construction in English.Step 5: Look at options A daclination and D daclineation. Both begin with dac, which does not correspond to the base decline and so appear random and incorrect.Step 6: Conclude that declination is the only correctly spelt option.

Verification / Alternative check:
You can verify by recalling common phrases such as the declination of the star or moral declination, where the noun refers to angle or moral decline. Dictionaries and textbooks consistently use declination, never declineation or the other forms. The word formation rule of dropping final e before ation further supports this spelling pattern. Therefore, option C is correct beyond doubt.

Why Other Options Are Wrong:
daclination and daclineation change the base decline into dacline or dacl, which is meaningless and violates the connection with the root word. declineation keeps the full verb decline and simply adds ation, resulting in an awkward and nonstandard form with repeated vowels. None of these appear in respectable English usage, so they are incorrect spellings.

Common Pitfalls:
Candidates often get confused when they see an option that contains the full base word plus a suffix, such as declineation, and may mistakenly think it looks more complete. Another mistake is to rely on sound alone, since declination and declineation sound similar when spoken. The safe method is to recall standard spelling rules and base word transformations, especially the treatment of silent e before ation.

Final Answer:
The correctly spelt word among the options is declination.