In the sonny blue story When the older brother is leaving work at the end of the day, someone is waiting outside. What best describes that other person's appearance, and how Brother felt about seeing him or her?

1. in which sentence is the underlined portion a predicate nominative? for astronauts, going into space to repair orbiting equipment becomes a challenge. for astronauts, going into space to repair orbiting equipment becomes tricky. for astronauts, going into space to repair orbiting equipment becomes challenging. for astronauts, going into space to repair orbiting equipment becomes frequent.