Final answer:
Public interest in the Challenger launch was extremely high due to Christa McAuliffe, a schoolteacher, being on board as part of the NASA Teacher in Space Project, which aimed to inspire students and the public.
Step-by-step explanation:
Public interest in the Challenger launch was so high primarily because of D) the presence of a schoolteacher on board. Christa McAuliffe, a high school social studies teacher, was selected from more than 11,000 applicants to participate in the NASA Teacher in Space Project. This initiative was aimed at inspiring students and the general public, and McAuliffe's inclusion on the Challenger crew sparked immense public enthusiasm and international media attention. Unfortunately, the Challenger disaster occurred on January 28, 1986, when the space shuttle broke apart 73 seconds into its flight, leading to the deaths of all seven crew members, including McAuliffe.
Another reason was the presence of a schoolteacher on board, Christa McAuliffe. She was selected to be the first civilian teacher in space, which garnered a lot of media attention and made the mission relatable to students and the general public.
Overall, the combination of being the first space shuttle launch in a long time and the presence of a schoolteacher on board contributed to the high public interest in the Challenger launch.