Question

in a multi electron atom which of the following orbitals described by 3 quantum numbers will have same energy in the absence of magnetic and electric fields??
a)n=1 m=0 l=0
b)n=2 l=0 m=0
c)n=2 m=1 l=1
d)n=3 l=2 m=1
e)n=3 l=2 m=0

options
1) a and b
2) b and c
3) c and d
4) d and e

explain the following wit reason

Answer 1

I think 1st one is right

Answer 2

3 c and a is the answer