In this English spelling question, identify the correctly spelled standard English word from the four options given.

Introduction / Context:

This question asks you to choose the correctly spelled English word out of four similar looking options. Spelling accuracy is important not only for exam performance but also for clear written communication in academic and professional settings. Among the four choices, only one matches standard dictionary spelling; the others contain deliberate errors such as extra consonants, wrong vowel combinations, or missing letters.

Given Data / Assumptions:

• The options are toxicety, mamalia, collumned, and notation.
• Only one of these words is correctly spelled according to standard English usage.
• You may or may not know the meanings, but recognising common suffixes and familiar roots can guide you.
• The question is purely about spelling, not about which word seems more technical or advanced.

Concept / Approach:

The word "notation" is a widely used term in mathematics, music, and other fields to refer to a system of symbols or signs. Its spelling is stable and familiar: n o t a t i o n. The other options appear to be distorted versions of real words. "Toxicity" is the correct spelling for a related concept about poison or harmfulness, not "toxicety". "Mammalia" is a scientific class name for mammals, not "mamalia". "Columned" is the correct past participle form meaning having columns, not "collumned". Recognising the roots "toxic", "mammal", and "column", and remembering their standard forms, allows you to see how each of those three options has been misspelled.

Step-by-Step Solution:

Verification / Alternative check:

If you think about example sentences, you might remember phrases such as "musical notation", "mathematical notation", or "chemical notation", all of which use exactly this spelling. In contrast, you are unlikely to have seen "toxicety" in any textbook, whereas "toxicity" is common. Similarly, biology books refer to "Mammalia", with two m letters after the initial letter, and architecture or art books use "columned", not "collumned". The fact that only "notation" fits both your reading experience and standard morphological patterns confirms that it is the correct answer.

Why Other Options Are Wrong:

"Toxicety" misrepresents the correct noun "toxicity" and uses the nonstandard ending "cety". "Mamalia" omits one m and therefore fails to match the accepted scientific term. "Collumned" incorrectly doubles the l in "column", which already contains a silent n and does not take an extra l. Examiners often create such near miss spellings to reward students who pay careful attention to letters and common suffixes.

Common Pitfalls:

Some candidates rely on a vague impression that scientific or technical words always have strange spellings, and they may therefore overtrust distorted forms like "mamalia" or "toxicety". Others skim quickly and do not notice small changes such as an extra l in "collumned". A reliable strategy is to identify the simplest, most familiar base word first and then add or check the suffix. When you see "notation", you can clearly link it to "note", and the pattern note plus ation is very regular in English.

Final Answer:

The correctly spelled word is notation.