[8 pts] In a room there are many professors ( P ) , counselors ( C ) and students ( S ) . Find the sample space of the following two-stage experiment: Stage 1: Flip a coin and record whether tails (T) or heads ( H ) shows up. Stage 2: If tails (T) shows up on stage 1 , select 1 person randomly from the room and record the type of person. If heads ( H ) shows up on stage 1 , flip the coin again and record whether tails or heads shows up. .