Answer: s sub level ↔ first energy level
s and p sub levels ↔ second energy level
s, p, and d sub levels ↔ third energy level
Step-by-step explanation:
As we know, s sub level is nearest to the nucleus and lies in 1st principal shell, while if we see s and p sub levels are lies in 2nd subshell and s,p and d sub levels are lies in 3rd principal shell.