From the following options, select the word that is spelt correctly in standard English.

Introduction:
This question assesses your ability to recognise correct English spelling among several similar looking options. Correct spelling is essential for clear written communication, and competitive exams often include such questions to test careful reading and familiarity with standard forms. Three of the options contain deliberate errors, while one matches the usual dictionary spelling.

Given Data / Assumptions:

- Options: infarnal, dorsally, somwhat, mangoose. - Only one of these is correctly spelt. - The correct word should appear in standard dictionaries without modification.

Concept / Approach:
The word dorsally is an adverb related to dorsal, which means relating to the back or upper side of an animal or organ. It is correctly formed by adding the suffix ly to the adjective dorsal. The other three options appear to be misspellings of known words: infarnal for infernal, somwhat for somewhat, and mangoose for mongoose. Recognising the correct base forms helps you quickly identify which spelling is acceptable.

Step-by-Step Solution:
Step 1: Look at infarnal and recall that the common adjective is infernal, meaning relating to hell or very bad. Step 2: Examine somwhat and remember that the correct spelling is somewhat. Step 3: Consider mangoose and recognise that the animal is spelled mongoose. Step 4: Check dorsally and recall that dorsal is a standard adjective and that dorsally is its adverbial form. Step 5: Conclude that dorsally is the only correctly spelt word among the options.

Verification / Alternative check:
Imagine sentences using each word. The sentence The fin is located dorsally on the fish looks scientifically correct. In contrast, The weather is infarnal or I feel somwhat tired immediately appear wrong if you are used to reading in English. Similarly, A mangoose ran across the road looks strange when you know the correct word is mongoose. This mental check reinforces that only dorsally matches standard usage.

Why Other Options Are Wrong:
Infarnal has an incorrect vowel arrangement and does not appear in reliable dictionaries. Somwhat is missing the letter e after m, which is present in somewhat. Mangoose replaces the double o in mongoose with a different pattern and is not recognised as standard spelling. Because exam questions on spelling require strictly correct forms, these three cannot be chosen as answers.

Common Pitfalls:
Sometimes students are tempted by very familiar words that are subtly misspelt, such as somwhat appearing similar to somewhat. To avoid this, you should read each option slowly and visualise it in a sentence or on a printed page. Regular reading of quality texts such as books and newspapers gradually builds a mental picture of correct spellings and makes it easier to spot wrong ones quickly in an exam.

Final Answer:
dorsally is the correctly spelt word among the given options.