4 d , 5 p , 5 f and 6 p orbitals are arranged in the order of decreasing energy. The correct option is:

$\mathrm{n}+\mathrm{l}$ values:

$4\mathrm{d}=4+2=6$

$5\mathrm{p}=5+1=6$

$5\mathrm{f}=5+3=8$

$6\mathrm{p}=6+1=7$

Sub-shell which has higher $\left(\mathrm{n}+\mathrm{l}\right)$ value, has more energy.

If $\left(\mathrm{n}+\mathrm{l}\right)$ is same for two sub-shells, then the one having more $\mathrm{n}$ value has more energy.

$5\mathrm{f}>6\mathrm{p}>5\mathrm{p}>4\mathrm{d}$