Which definition of the time designation BCE is correct

Simply put, BCE (Before Common Era) is a secular version of BC (before Christ). CE (Common Era) is the secular equivalent of AD (anno Domini), which means “in the year of the Lord” in Latin. January 1, 45 BCE (Before Common Era), or – if you prefer – on January 1, 45 BC (before Christ)

Explanation:

these civilizations were located around fertile rivers, where they could produce an abundance of crops

the award is named for an american naval historian and theorist, rear admiral alfred thayer mahan, united states navy who, through his writing, provided stimulus and guidance to those who share in the defense of the nation.