If you want to locate someone precisely on the surface of the Earth, you specify her exact latitude and longitude. If you want to locate a star precisely on the sky, you need to specify its exact:
A) meridian and great circle
B) constellation
C) north and east point
D) right ascension and declination
E) solstice and equinox

D) right ascension and declination

Explanation:

Just like we have a longitude on earth which tells us about the position or angular measurement of a body east or west of Greenwich that lies at 0° longitude, for the measurement of star's position on the sky we use RA (right ascension) that tells us about the position of star from celestial equator.

              As the latitude provide us the information of position in north or south of the equator, similarly declination tells the position of star in the north or south of celestial equator.

So if some one wants to locate the star more precisely on the sky then he/she will measure and describe it in terms of right ascension and declination.

answer; ///i believe that the correct answer is when the same ( isobar ) passes through two locations on a weather map,both locations have the same pressure;