Select the correctly spelled English word from the following options.

Introduction / Context:
This spelling question checks whether you can recognise the standard English spelling of common words. Examinations often mix one correct spelling with several distractors that look similar but contain extra letters, missing letters, or incorrect vowel combinations. Being able to spot such errors is important for accurate writing in competitive exams and formal communication.

Given Data / Assumptions:

• Four options are given: "pamflet", "montaage", "illusary", and "stroller".
• Only one of these is spelled correctly in standard English.
• No additional context is needed; the task is pure spelling recognition.

Concept / Approach:
To solve spelling questions, you can:

• Draw on your reading experience of newspapers, books, and reliable web sources.
• Break the word into familiar roots or syllables.
• Notice common spelling patterns in English, such as "ph" for the sound /f/ in "pamphlet".

Words taken from other languages (especially French or Latin) often keep specific letter combinations that you may have seen before in print.

Step-by-Step Solution:
Step 1: Examine "pamflet". The correct word for a small booklet is "pamphlet", with "ph" instead of "f". So "pamflet" is incorrect. Step 2: Look at "montaage". It clearly resembles "montage", which is a film and art term. The extra "a" makes it wrongly spelled. Step 3: Consider "illusary". The correct adjective derived from "illusion" is "illusory", with "o" before "r", not "a". Step 4: Check "stroller". This is a common English word for a baby carriage or a person who strolls. It is correctly spelled with double "l".

Verification / Alternative check:
You can quickly verify using familiar related forms:

• "Pamphlet" is how it appears in textbooks and pamphlets themselves.
• "Montage" is common in film studies ("a rapid montage of scenes").
• "Illusory" appears in phrases like "illusory promises".
• "Stroller" for a baby's pushchair is written exactly as in option D.

Only "stroller" matches the standard dictionary spelling without alteration.

Why Other Options Are Wrong:

• pamflet: Wrong because it replaces "ph" with "f" and removes the "h".
• montaage: Incorrect double vowel in the middle; standard English uses "montage".
• illusary: Incorrect vowel; the accepted form is "illusory".

Common Pitfalls:
A frequent mistake is to trust how a word sounds instead of how it is conventionally spelled, especially in words borrowed from French, where letters like "ph" and silent "e" are common. Another pitfall is to overlook double consonants or extra vowels added to confuse you. Regular reading of quality English material naturally improves your spelling memory and reduces such errors.

Final Answer:
The only correctly spelled word is stroller.