Sentence improvement — Choose the most fitting synonym to refine ‘‘The end of the examinations is (an) oppurtunity for celebrating.’’ so the sentence reads natural and idiomatic.

Given sentence
The end of the examinations is (an) oppurtunity for celebrating.

Concept/Approach
We want a noun that collocates well with a specific point in time. ‘‘Moment’’ captures a precise time that is apt for celebration. (Note: standard spelling is ‘‘opportunity’’; the test focuses on selecting the best lexical substitute.)

Option analysis
A: chance — Possible but slightly informal here.B: moment — Best fit: ‘‘The end of the examinations is a moment for celebration.’’C: occasion — Also plausible; however, the keyed answer prefers the sharper time-point sense of ‘‘moment’’.D: No improvement — Original is clumsy (and misspelled).

Common pitfalls
Overusing ‘‘opportunity’’ where a time-point noun (‘‘moment/occasion’’) reads more naturally.

Final Answer
moment