How Does the Kepler Mission Plan to Detect Earth-Like Planets

Multiple Choice

How does the Kepler mission plan to detect Earth-like planets around other stars?

A) by measuring the Doppler shift in spectral lines as the central star is tugged to and fro by the planet
B) by observing the slight dip in brightness of the central star as the planet transits
C) by directly imaging the planet
D) by observing the spectrum of the planet
E) by measuring the slight shift in position of the central star as it is tugged to and fro by the planet