Choose the statement that is NOT true.
a. More than 50% of the 100 billion stars in the Milky Way galaxy have at least one planet orbiting.
b. Planets orbiting stars in the "habitable zone" are likely to have life existing on them.
c. The first Earth-size planets ever found outside the solar system were discovered in 2012 by the Kepler Mission team.
d. Hundreds of stars with planets have been confirmed using the radial velocity method and the transit method.