The astronomical unit (au) is the mean distance from the sun to the earth. 1 au = 1.5 × 10,superscript,8,baseline, km (kilometers) if a comet is 2.3 au from the earth, how many km away is the comet? answer options with 5 options a. 3.45 × 10,superscript,8,baseline, km b. 6.52 × 10,superscript,7,baseline, km c. 3500 km d. 3.45 × 10,superscript,10,baseline, km e. 6.52 × 10,superscript,10,baseline, km