In this spelling question on everyday English, four alternatives are given; choose the correctly spelt form of the common noun “vacuum”.

Introduction / Context:
The word “vacuum” is widely used in physics, science classes and daily life (for example, vacuum cleaner, vacuum packing). Because the pronunciation does not clearly show how many “c” or “u” letters appear in the spelling, exam setters often use it in spelling questions. You are given four close variants and asked to select the correctly spelt word. This is a straightforward but important test of your ability to recognise common English spellings.

Given Data / Assumptions:

• The options are: vaccum, vacuum, vacum, vaccuum.
• Only one option corresponds to standard English spelling.
• The question does not involve grammar or meaning, only spelling accuracy.

Concept / Approach:
The correct spelling of the word is “vacuum”, with the sequence v-a-c-u-u-m. So there is only one “c” and two consecutive “u” letters. Many incorrect forms either double the “c” or reduce the “u” letters to one. To solve such items, you should recall the correct pattern, then systematically check each option for the number and order of consonants and vowels. This conscious checking is safer than relying only on how the word “looks”.

Step-by-Step Solution:
Step 1: Recall the standard spelling “vacuum” as v-a-c-u-u-m. Step 2: Check option a) “vaccum”. Here the “c” is doubled (c-c), and the double “u” is missing. This is incorrect. Step 3: Check option b) “vacuum”. This matches the correct pattern: one “c” and double “u”. Step 4: Check option c) “vacum”. It contains only one “u”, so it is wrong. Step 5: Check option d) “vaccuum”. Both the “c” and the “u” are doubled, giving “ccuu”. This differs from the standard spelling. Step 6: Conclude that option b) “vacuum” is the only correctly spelt form.

Verification / Alternative check:
A quick verification method is to recall familiar phrases such as “vacuum cleaner” or “in a vacuum”. If you have seen the word in school books or science notes, you will remember that there is a “cuu” sequence. Another memory tip is to think of “vac + uum” where “uum” reminds you of the twin “u” letters. Matching this mental pattern against the options quickly confirms that “vacuum” is correct and the others are faulty variants created just to confuse you.

Why Other Options Are Wrong:
“Vaccum” wrongly doubles the “c” and drops one “u”. “Vacum” looks simpler but is missing the second “u”, which is essential. “Vaccuum” adds extra letters by doubling both “c” and “u”, which does not match any standard dictionary form. Examiners use such close but incorrect spellings to test whether you have actually internalised the correct form rather than relying on guesswork.

Common Pitfalls:
Candidates often rely on approximate visual memory and choose the option that appears “more complex”, assuming the longest or strangest spelling must be right. Others ignore the fact that English sometimes uses double vowels, and they instinctively favour shorter forms like “vacum”. To avoid mistakes, train yourself to remember a small set of tricky words with their exact letter counts, including where double letters occur. Writing such words a few times while revising can fix them firmly in memory.

Final Answer:
The correctly spelt word is vacuum.