There are 3 players: A 240* 1+240*50%*3=600.

B 240*( 1+3)*60%=576

Option b

With 4 people: A 240* 1+240*50%*4=720.

B 240*( 1+4)*60%=720

All the same.

Five people: A 240* 1+240*50%*5=840.

B 240*( 1+5)*60%=864

Choose a piece of armor