Code is valid JSON equivalent of the key/value pair shown that also preserves the original value: UPC: 043875 code example

Example: Code is valid JSON equivalent of the key/value pair shown that also preserves the original value: UPC: 043875

Code is valid JSON equivalent of the key/value pair shown that also preserves the original value: 
UPC: 043875 


UPC: "04"
"UPC" : 04
Which one?