Which is the nearest star from our Solar system?
The correct option is B : Proxima Centauri
Alpha Centauri is not a star, but really a star system. Of the three stars in the system, the dimmest - called Proxima Centauri - is actually the nearest star to the Sun. The two bright stars, called Alpha Centauri A and B form a close binary system; they are separated by only 23 times the Earth - Sun distance. This is slightly greater than the distance between Uranus and the Sun.
The two main stars, Alpha Centauri A and Alpha Centauri B, are at an average of 4.3 light-years from Earth. Proxima Centauri is slightly closer at 4.25 light years.