Final answer:
The Sun is classified as spectral type G2, falling under the G category of main-sequence stars that represent stars like our own in terms of temperature.
Step-by-step explanation:
In the spectral sequence of star types, the Sun is classified as a A. Spectral type-O main-sequence star B. Spectral type-B main-sequence star C. Spectral type-A main-sequence star D. Spectral type-G main-sequence star E. Spectral type-M main-sequence star. The spectral classes are indicative of a star's temperature and are subdivided into 10 subclasses, with 0 being the hottest and 9 being the coolest within each type. The Sun, with its spectral type of G2, falls into the G category, notable for yellow main-sequence stars like our own Sun, and is classified as warmer than a G9 but cooler than a G0.