The correct answer is: "in other words"
The phrase, ""in other words" is the best replacement for the word, "or" at the beginning of the second sentence, because, using this phrase provides a smoother and clear transition from the first sentence to the second sentence. Compared to the other options, "in other words" is the best option, because both the first sentence and the second sentence basically convey the same idea. Replacing the word, "or" at the beginning of the second sentence, with "in other words", makes the sentences sound more effective and clear:
"A database is a collection of electronic information that can be accessed using a set of software commands. In other words, a database is a set of organized information (electronic) manipulated by a software."