Which of the following sentences contains a double negative?

This candy is very sweet.
This candy isn’t very sweet.
This candy is hardly sweet.
This candy isn’t hardly sweet.

Respuesta :

"This candy isn't hardly sweet," and the parts that make up the double negative are the words "is not" and "hardly," as they both hint at a "lack of" something. 
Pretty sure it's the last one. Isn't and hardly basically mean the same thing