Select the correctly spelled English word from the following options.

Introduction / Context:
This question tests basic English vocabulary and spelling recognition. Competitive exams often include one item where the learner has to identify the correctly spelled word among several near spellings. Such questions check whether candidates can visually recognise standard dictionary forms. Here the focus is on the correct spelling of a common food item that appears in newspapers, menus, and travel writing, namely the word couscous.

Given Data / Assumptions:

• The learner is given four spellings that look similar to real English words.
• Only one option reflects the correct standard spelling according to good dictionaries.
• No external context is required; this is a pure spelling recognition task.
• The aim is to choose the option that would appear in a reliable English dictionary.

Concept / Approach:
To solve spelling questions, a learner should mentally compare each option with known words, recall prior exposure in books or media, and use knowledge of common English spelling patterns. Some options will look odd because they double the wrong consonant or misplace vowels. The task is to carefully scan each option, silently pronounce it, and ask whether it matches the familiar form. When a candidate has read about international cuisine or seen recipes, they may already know that couscous is a North African dish whose name appears frequently in English cookbooks with a fixed spelling. The approach is therefore based on exposure to authentic usage and pattern recognition rather than formal rules alone.

Step-by-Step Solution:
Step 1: Read the instruction and understand that only one spelling is correct. Step 2: Look at option a, extoled. The intended base word seems to be extolled. The form extoled does not match the standard spelling. Step 3: Look at option b, couscous. This is a known food item, and this spelling appears in reliable sources such as menus and articles about North African food. Step 4: Look at option c, infernall. The correct related word is infernal with a single l at the end, so infernall is incorrect. Step 5: Look at option d, conceriti. There is no common English word with this exact spelling, so it is not acceptable. Step 6: Conclude that couscous is the only correctly spelled English word among the options.

Verification / Alternative check:
A quick mental check can be done by imagining a dictionary entry or recalling how these words appear in serious writing. Extolled is seen with double l and double d, infernal with a single l, and couscous exactly as given in option b. When three spellings clearly deviate from well known forms and one matches widely accepted usage, the answer is confirmed. If available, a learner could later verify with an actual dictionary, but in an exam environment, familiarity and reading habit act as the main verification method.

Why Other Options Are Wrong:
extoled: This is a misspelling; the correct past form is extolled, not extoled.
infernall: The final double l is incorrect; the standard word is infernal with one l at the end.
conceriti: This does not correspond to any common English word and is simply an invented distractor.

Common Pitfalls:
Candidates may be tempted by options that look vaguely familiar because they resemble real words. Under exam pressure, the eye may gloss over small differences like a missing consonant or an extra letter. Another pitfall is overthinking and doubting a familiar word such as couscous just because it looks foreign. Learners should trust genuine reading experience and remember that many loanwords from other languages enter English with stable spellings that do not change across contexts. Regular reading of newspapers, high quality blogs, and books naturally strengthens this instinct.

Final Answer:
The correctly spelled word is couscous, so option b is correct.