Step 1: Understand the task.
We must choose the word that is spelt correctly. Only one of the four options uses the right letters.
Step 2: Know the word's meaning.
The word means upkeep, the act of keeping something in good condition. For example, the maintenance of roads is important.
Step 3: Recall the correct spelling.
The right spelling is m-a-i-n-t-e-n-a-n-c-e. Notice the middle is 'ten' and the ending is 'ance'.
Step 4: Check the wrong options.
'Maintenence' wrongly ends in 'ence'. 'Maintanance' wrongly uses 'tan' in the middle. 'Meintenance' wrongly starts with 'mei'. All three break the correct pattern.
Step 5: Confirm the right one.
Only 'maintenance' keeps the 'main' start, the 'ten' middle, and the 'ance' ending all correct.
Step 6: State the conclusion.
The correctly spelt word is 'maintenance'.
\[ \boxed{\text{maintenance}} \]