Existing telescopes are capable of detecting radio signals similar to those generated by humans from any star around which planets have been detected. а. stars in giant elliptical galaxies since these stars, being oldest, are most likely to have advanced civilizations. b. any star within a 100 pc or so of the solar system. С. d. about a dozen or so of the closest star

Existing telescopes are capable of detecting radio signals similar to those generated by humans from any star around which planets have been detected. а. stars in giant elliptical galaxies since these stars, being oldest, are most likely to have advanced civilizations. b. any star within a 100 pc or so of the solar system. С. d. about a dozen or so of the closest star