The Reason That Most Extrasolar Planets Discovered by the Doppler

Multiple Choice

The reason that most extrasolar planets discovered by the Doppler technique are found close to their parent stars is

A) the wavelength shift of the star's spectrum is larger.
B) they transit more frequently, and have thus been more likely to be detected in the short time we have been searching for them.
C) more of the starlight is blocked by the planet when it transits the star.
D) the closer to a star, the hotter and therefore brighter the planet is.
E) planets that are close to a star are heated up and therefore larger.