Which argumentative statement contains a logical fallacy?

A) I simply cannot believe that putting blinds up on our hallway windows will increase students' ability to concentrate.
B) The cost of putting up blinds over the classroom hallway windows will be well worth the result of less student distraction.
C) Putting up blinds over the classroom hallway windows will help reduce student distractions from people walking during classes.
D) Many students, who find the classroom hallway windows distracting, will be able to concentrate better once blinds are placed over the windows.