What method has detected the most extrasolar planets (or candidates) so far? (a) the transit method.

What method has detected the most
extrasolar planets (or candidates) so far? (a) the transit method (b) Hubble
images (c) the Doppler method

What fraction of extrasolar planets could
in principle be detected by the transit method? (a) less than about 1% (b)
about 20% (c) 100%