Which type of orbital will be occupied by the electrons of highest energy for the In + ground-state ion?

The highest energy electrons will be occupying 5 s orbitals in In + ground state.

Explanation:

The atomic number of Indium is 49. So it means it has 49 electrons. According to Aufbau principle, the electronic configuration of In is [Kr] 4d10 5s2 5p1. So if the In is considered to be in In + state, this means 1 electron will be removed from the stable configuration of In.

Usually the electron in the outermost shell will be removed or ejected on transformation into an ion from an atom. So here Indium will be loosing the electron from 5 p orbital. So, then the highest energy of the In + ground state ion will in 5 s orbital only.