Petra is making necklaces to sell at a craft fair. The hardware for each necklace costs $3.75,
and each bead costs $0.50. The number of beads Petra needs depends on the design she
chooses. Which expression gives the total cost to make 30 necklaces with b beads?
30 (4.25b)
30 (3.75b + 0.5)
30 (0.55 +3.75)
30 (0.5b) + 3.75