The emission of photons takes place when an electron from higher energy orbitals jumps to a lower energy orbital.
Therefore the light emitted will correspond to the energy difference between the orbitals.
When the atom emits the photons, they will have energy equal to the energy difference between the orbitals of the Hydrogen. Therefore the spectrum obtained by the hydrogen gas will contain only those lines which correspond to the energy difference of the orbitals.
Therefore the hydrogen will emit a spectrum that contains a series of emission lines spaced in a mathematical sequence.
Therefore the correct answer is option C.