Scissors should never be ___________ by the handle.

The correct answer is "carried" because it is the appropriate past participle form of the verb "carry," which is necessary for the passive voice construction in this sentence. The sentence implies that scissors should not be moved or transported in a specific manner (by the handle), and the passive voice is used to emphasize the scissors and the action being done to them, rather than who is doing the action.

In the context of the sentence, "should never be carried by the handle" indicates that there is an advice or warning regarding the proper handling of scissors. The phrase "should be" indicates a passive construction that requires a past participle.

Using any of the other options would create grammatical errors. "Carry" is a base form, which does not fit in the passive construction. "Carries" is the third-person singular present tense form, which is also inappropriate here. "Carrying," the present participle, would suggest an ongoing action but does not align with the intended passive meaning of the sentence.