Mark 15 study questions

Why does the crowd ask for Barabbas? Were there no other options for Pilate to release apart from Barabbas and Jesus? Was Barabbas actually popular? (v 7)

Why did the crowd think Jesus was calling Elijah? (v 35)

What was it that made the centurion convinced that Jesus was the son of God? (v 39)

Was Joseph of Arimathea in the trial of Jesus? How can we learn from the courage he shows here seeking the body of Jesus? (v 43)