Which word correctly completes the sentence: Jane ___ broke the ceramic vase?

The word "accidentally" is the correct choice to complete the sentence because it is the proper spelling of the adverb that means something happened unexpectedly or by chance, without intention. In the context of the sentence, it modifies the verb "broke," conveying that Jane did not intend to break the ceramic vase.

The other choices are misspellings or incorrect versions of the word. The adverb needs to be spelled with two 'c's and two 'l's to conform to standard English usage, which is why "accidentally" is the appropriate word here. This choice effectively communicates both the nature of the action and its unintentionality.