What is the highest level of normalization the table below achieves?

students table

student$\_$id student$\_$name course$\_$ids credit$\_$hours

$1101$ Maliya Jones $[571,643,112]10$

$1288$ Eduardo Lopez $[615,643]6$

$1312$ Jennifer McCormick $[571,113,212,890,315]15$

$1470$ Pei Whang $[615,643,212,441,611]17$

Question $4$ options:

a$)$

$3$NF

b$)$

$2$NF

c$)$

$1$NF

d$)$

This table is not normalized