In the given figure, the energy levels of hydrogen atom have been shown along with some transitions marked A, B, C, D and E. The transitions A, B and C respectively represent

$$\text{Transition A: From the continuum } (n_i = \infty) \text{ to } n_f = 1.$$

$$\text{Transitions ending at } n_f = 1 \text{ belong to the Lyman series. A transition from } \infty$$ represents the shortest wavelength / maximum energy, known as the series limit

$$\therefore \text{Transition A represents the series limit of Lyman series.}$$

$$\text{Transition B: From } n_i = 5 \text{ to } n_f = 2.$$

$$\text{Transitions ending at } n_f = 2 \text{ belong to the Balmer series.}$$

$$\text{The members are ordered by descending energy steps: } n_i=3\,(1^{\text{st}}\text{ member}), \ n_i=4\,(2^{\text{nd}}\text{ member}), \ n_i=5\,(3^{\text{rd}}\text{ member}).$$

$$\therefore \text{Transition B represents the third member of Balmer series.}$$

$$\text{Transition C: From } n_i = 5 \text{ to } n_f = 3.$$

$$\text{Transitions ending at } n_f = 3 \text{ belong to the Paschen series.}$$

$$\text{The members are ordered by descending energy steps: } n_i=4\,(1^{\text{st}}\text{ member}), \ n_i=5\,(2^{\text{nd}}\text{ member}).$$

$$\therefore \text{Transition C represents the second member of Paschen series.}$$