The increasing order of energy of the orbitals 3 s,3 p,3d ,4f  is

The increasing order of energy of the orbitals is depend on both n and l values. If the n +l value is greater for one orbital it has high energy than other orbitals with their n l + value is minimum. Here, the given 3 ,3 ,3 and 4 s pd s orbitals having n l + values are 3+0=3,3+1=4,3+2=5&4+0=4 respectively. Therefore, the increasing order of energy of the orbitals.

3s,3p,3d,4s is 3s<3p<4s<3d