Which of the following orbital has most energy in multi-electron system?
4d
Try to use Bohr - Bury rule of (n + l) here.
→ Whichever is having more value of (n + l) value will have more energy.
⇒ 3s ⇒ 3 + 0 = 3
⇒ 4p ⇒ 4 + 1 = 5
⇒ 3d ⇒ 3 + 2 = 5
⇒ 4s ⇒ 4 + 0 = 4
Now, between 3d and 4p, because they have same (n + l) value, whichever orbitals 'n' is greater, will have more energy.
So, 4p will have most energy.