The Paschen series is a set of spectral lines emitted by atoms when an electron transitions from a higher energy level to the third energy level (n=3). The initial state (n1) refers to the energy level from which the electron transitions.

The correct answer for the initial state (n1) in the Paschen series is option 'C' (n1 = 3).

Explanation:

1. Paschen series:
- The Paschen series is a series of spectral lines in the electromagnetic spectrum that corresponds to transitions of electrons in hydrogen atoms.
- These transitions occur when an electron drops from a higher energy level to the third energy level (n=3) in the hydrogen atom.

2. Energy levels in hydrogen atom:
- The hydrogen atom has discrete energy levels, which are represented by the principal quantum number (n).
- The energy levels are labeled as n=1, n=2, n=3, and so on, with n=1 being the ground state (lowest energy level).

3. Transitions in the Paschen series:
- In the Paschen series, the electron transitions from a higher energy level (n2) to the third energy level (n=3).
- The transitions can be represented as n2 -> 3, where n2 is the initial energy level.

4. Determining the initial state (n1):
- To determine the initial state (n1), we need to consider the transitions that lead to the third energy level (n=3).
- The possible initial states can be n1=2, n1=4, n1=3, and n1=1.
- However, the correct option is n1=3, as stated in the question.

In summary, the initial state (n1) for the Paschen series is n1=3. This means that the electron transitions from a higher energy level to the third energy level (n=3) in the hydrogen atom.