If Angle DBC is 73, you do subtract it from 180 to get ABD.
180 - 73 = 107
Angle ABD = 107 Angle DBC = 73
Angle ABD > DBC or Angle DBC < ABD
The line BD/DB is the same length in both angles, proving line AD is greater than CD. This is also justified by the fact that lines AB and CB are congruent.
I hope this helps, let me know if there's something wrong about my answer.
The unit price for option 1 is $0.68 for each candy bar. The unit price for option 2 is $0.60. So you would be getting more candy bars for your money with the second option. I hope this helps!