In the following question, four words are given. Out of these, one word is incorrectly spelt. Select the incorrectly spelt word.

Introduction / Context:
This is another spelling question that checks whether you can spot a common error among everyday English words. Such questions are important because incorrect spellings in exams, applications, or professional writing can leave a poor impression. Here you are required to identify which one of the four given words is not correctly spelt according to standard English usage.

Given Data / Assumptions:
- Options:
- Familiar.
- Grammer.
- Narrator.
- Operator.
- Only one spelling is incorrect; the others appear in standard dictionaries exactly as shown.

Concept / Approach:
The key word here is "grammar", which is frequently misspelt as "grammer". Grammar refers to the system and structure of a language. The other words—familiar, narrator, and operator—are correctly written. Therefore, the misspelt word is "Grammer".

Step-by-Step Solution:
Step 1: Look at "Familiar". This adjective, meaning well-known or easily recognised, is correctly spelt F-a-m-i-l-i-a-r.Step 2: Look at "Grammer". The correct word for the rules and structure of a language is "grammar", spelt G-r-a-m-m-a-r. The option uses "e-r" instead of "a-r", making it incorrect.Step 3: Look at "Narrator". This noun, meaning the person who tells the story, is correctly spelt N-a-r-r-a-t-o-r.Step 4: Look at "Operator". This noun is correctly spelt O-p-e-r-a-t-o-r and is commonly used for a machine operator or telephone operator.Step 5: Since only "Grammer" does not match the standard dictionary spelling, it is the incorrectly spelt word.

Verification / Alternative check:
Recall how the subject is written in school textbooks: "English Grammar". Also consider related forms, such as "grammatical", which clearly show the "a" after "m". No common English resource uses "grammer" as a correct spelling. In contrast, "familiar narrator" and "telephone operator" are collocations you may have seen multiple times with the spellings provided here. This confirms the identification of the error.

Why Other Options Are Wrong (that is, correct spellings):
- Familiar: Correctly spelt; used in phrases like "familiar place" or "familiar face".
- Narrator: Correctly spelt; widely used in literature and film studies.
- Operator: Correctly spelt; used in both everyday and technical contexts.

Common Pitfalls:
Words that refer to language study, such as grammar, vocabulary, and pronunciation, are often misspelt because learners rely on phonetic guesses. The double "m" and final "ar" in "grammar" cause confusion, leading to forms like "grammer". It helps to remember related words like "programmer" to note that although "programmer" uses "m-e-r", the language term uses "m-a-r". Building personal lists of frequently misspelt words and revising them regularly can greatly reduce such mistakes in exams.

Final Answer:
The incorrectly spelt word is "Grammer"; the correct spelling is "Grammar".