Answer: (sidenote, I'm sorry if I answered incorrectly ;-;)
C: 4/5 or D 5/4
Step-by-step explanation:
if you solve the numbers inside the radical symbol you'll get 16807. it's hard for it to be separated into 4 groups since it can only be separated in 5, that being 7*7*7*7*7.
so, by process of elimination i suggest you answer either c or d