C.The main part of the Cathedral of Notre Dame was completed in 1250 C.E.
Explanation:
The new abbreviations for time related terms are BCE and CE, and were chaged because the old ones made reference to the existence of Jesus, they were befor christ and anno domini, which is latin for the year of the lord, so now they are Before Common Era, and Common Era, and when doing time related terms you always have to put the year first and the abbreviation after, so the only one that uses the correct terms and puts the year first would be C.
