Which of the following is the approximate number of confirmed exoplanets discovered by NASA's Kepler program?

The approximate number of confirmed exoplanets discovered by NASA's Kepler program is around 2,327. This figure reflects the significant contributions of the Kepler mission, which was launched to survey a portion of our galaxy for transiting exoplanets. Kepler utilized a photometric method to detect variations in brightness that indicate the presence of planets as they transit in front of their host stars. This extensive survey led to a wealth of data, resulting in a large catalog of confirmed exoplanets by the end of the mission.

The number presented in the correct answer highlights the successful detection techniques and the broad scope of Kepler's mission, as it was aimed specifically at identifying planets in the habitable zones of stars, among other areas of interest in exoplanet research. This mission has significantly enhanced our understanding of planetary systems beyond our own. Thus, the confirmed number of 2,327 serves as a landmark figure that illustrates the progress made in the field of exoplanet discovery during the Kepler mission.